Recording and/or reproduction apparatus, file management method and providing medium

ABSTRACT

The invention provides a file system which can record and/or record AV signals simply onto and/or from a disc in a home. The file system is incorporated in a recording and/or reproduction apparatus which uses a disc type recording medium, and records management information for management of a file of AV data to at least two locations of a logical volume.

BACKGROUND OF THE INVENTION

[0001] This invention relates to a recording and/or reproductionapparatus, a file management method and a providing medium, and moreparticularly to a file system to be used for a recording and/orreproduction apparatus (VDR: Video Disc Recorder) in which a disc typerecording medium is used.

[0002] As a file system for recording data onto a disc type recordingmedium, the ISO/IEC13346, 1995, “Information technology—Volume and filestructure of write-once and rewritable media using non-sequentialrecording for information interchange” is known. This file system is ageneral purpose file system for recording various data and is notintended to be used by an individual to record compressed digital AV(audio and vide) signals onto a disc in a home. Therefore, the system isnot necessarily satisfactory to record compressed digital AV (audio andvideo) signals. Accordingly, a file system and a volume optimum torecord AV signals are demanded.

SUMMARY OF THE INVENTION

[0003] It is an object of the present invention to provide a recordingand/or reproduction apparatus, a file management method and a providingmedium which can be applied to a file system with which an individualcan record and reproduce AV signals onto and from a disc readily in ahome.

[0004] In order to attain the object described above, according to anaspect of the present invention, there is provided a recording and/orreproduction apparatus for recording and/or reproducing AV data ontoand/or from a disc type recording medium, comprising first recordingmeans for recording a file of AV data, and second recording means forrecording management information for the file to at least two locationsof a logical volume.

[0005] According to another aspect of the present invention, there isprovided a file management method for a recording and/or reproductionapparatus for recording and/or reproducing AV data onto and/or from adisc type recording medium, comprising a first recording step ofrecording a file of AV data, and a second recording step of recordingmanagement information for the file to at least two locations of alogical volume.

[0006] According to a further aspect of the present invention, there isprovided a providing medium for providing a program which can be read bya computer for causing a recording and/or reproduction apparatus forrecording and/or reproducing AV data onto and/or from a disc typerecording medium to execute a first recording step of recording a fileof AV data, and a second recording step of recording managementinformation for the file to at least two locations of a logical volume.

[0007] In the recording and/or reproduction apparatus, the filemanagement method and the providing medium, a file of AV data isrecorded and management information is recorded to at least twolocations of a logical volume. Consequently, an individual can recordand/or reproduce compressed video and audio signals simply in a home.

[0008] According to a still further aspect of the present invention,there is provided a recording and/or reproduction apparatus, comprisingunit recording means for recording units of information which can berecorded onto a disc type recording medium, setting means for settinglengths of the units of information to be recorded by the unit recordingmeans, and identification information recording means for recording, inresponse to a file recorded on the disc type recording medium,identification information for identification of the length of the unitadopted when the file is recorded from among the units of the length setby the setting means.

[0009] According to a yet further aspect of the present invention, thereis provided a file management method for a recording and/or reproductionapparatus for recording and/or reproducing information onto and/or froma disc type recording medium, comprising a unit recording step ofrecording units of information which can be recorded onto the disc typerecording medium, a setting step of setting lengths of units ofinformation to be recorded in the unit recording step, and anidentification information recording step of recording, in response to afile recorded on the disc type recording medium, identificationinformation for identification of the length of the unit adopted whenthe file is recorded from among the units of the length set by thesetting means.

[0010] According to a yet further aspect of the present invention, thereis provided a providing medium for providing a program which can be readby a computer for causing a recording and/or reproduction apparatus forrecording and/or reproducing AV data onto and/or from a disc typerecording medium to execute a unit recording step of recording units ofinformation which can be recorded onto the disc type recording medium, asetting step of setting lengths of units of information to be recordedin the unit recording step, and an identification information recordingstep of recording, in response to a file recorded on the disc typerecording medium, identification information for identification of thelength of the unit adopted when the file is recorded from among theunits of the length set by the setting means.

[0011] In the recording and/or reproduction apparatus, the filemanagement method and-the providing medium, units of recordableinformation are recorded onto a disc type recording medium and thelengths of the units of information to be recorded are set and then, inresponse to a file to be recorded onto the disc type recording medium,the length of a unit adopted when the file is recorded is identifiedfrom among the set units of the length. Consequently, an individual canrecord and/or reproduce compressed video and audio signals simply in ahome.

[0012] The above and other objects, features and advantages of thepresent invention will become apparent from the following descriptionand the appended claims, taken in conjunction with the accompanyingdrawings in which like parts or elements denoted by like referencesymbols.

BRIEF DESCRIPTION OF THE DRAWINGS

[0013]FIG. 1 is a diagrammatic view illustrating a format of an entiredisc type recording medium;

[0014]FIG. 2 is a diagrammatic view illustrating an anchor descriptor;

[0015]FIG. 3 is a diagrammatic view illustrating a logical volume;

[0016]FIG. 4 is a flow chart illustrating a procedure of setting thelength of an allocation extent;

[0017]FIG. 5 is a schematic view showing an example of a screen to beused to set the length of an allocation extent;

[0018]FIG. 6 is a flow chart illustrating a procedure of recording afile;

[0019]FIG. 7 is a schematic view showing a screen to be used to selectthe length of an allocation extent;

[0020]FIG. 8 is a view illustrating a volume structure descriptor;

[0021]FIG. 9 is a view illustrating a media information descriptor;

[0022]FIG. 10 is a view illustrating a drive information descriptor;

[0023]FIG. 11 is a view illustrating an extended data descriptor;

[0024]FIG. 12 is a diagrammatic view illustrating a file system;

[0025]FIG. 13 is a diagrammatic view illustrating a child link, a nextlink and a parent link;

[0026]FIG. 14 is a view illustrating a file table;

[0027]FIG. 15 is a view illustrating a file table of the file tablestructure type 0;

[0028]FIG. 16 is a view illustrating an allocation extent table;

[0029]FIG. 17 is a view illustrating an allocation strategy table;

[0030]FIG. 18 is a view illustrating an extended attribute table;

[0031]FIG. 19 is a block diagram showing a construction of a recordingand/or reproduction apparatus to which the present invention is applied;

[0032]FIGS. 20A and 20B are diagrams illustrating a relationship betweenthe amount of data stored in a buffer of the recording and/orreproduction apparatus of FIG. 19 and the rate of data written into thebuffer;

[0033]FIG. 21 is a diagrammatic view illustrating a structure of a filerecorded on an optical disc used on the recording and/or reproductionapparatus of FIG. 19;

[0034]FIGS. 22A, 22B, 22C and 22D are diagrams illustrating aconstruction of a file used in the recording and/or reproductionapparatus of FIG. 19 and the amount of data stored in the buffer;

[0035]FIG. 23 is a diagrammatic view illustrating another constructionof a file recorded on the optical disc used in the recording and/orreproduction apparatus of FIG. 19;

[0036]FIGS. 24A, 24B, 24C and 24D are diagrams illustrating thestructure of the file illustrated in FIG. 23 and the amount of datastored in the buffer of the recording and/or reproduction apparatus ofFIG. 19;

[0037]FIGS. 25A and 25B are diagrammatic views illustrating processingrecording a file into blocks;

[0038]FIG. 26 is a flow chart illustrating a procedure of recording datainto blocks;

[0039]FIGS. 27A and 27B are diagrammatic views illustrating a procedureof dividing a file recorded in a block;

[0040]FIGS. 28A and 28B are diagrammatic views illustrating anotherprocedure of dividing a file recorded in a block;

[0041]FIGS. 29A and 29B are diagrammatic views illustrating a furtherprocedure of dividing a file recorded in a block;

[0042] FIGS. 30 to 32 are flow charts illustrating different proceduresof dividing a file;

[0043]FIGS. 33A and 33B are diagrammatic views illustrating a procedureof compressing free areas of blocks; and

[0044]FIG. 34 is a flow chart illustrating a procedure of compressingfree areas of blocks.

DESCRIPTION OF THE PREFERRED EMBODIMENT

[0045] First, a format system for a disc type recording medium to whichthe present invention is applied is described. Referring to FIG. 1,there is illustrated a format of an entire recording medium. Therecording medium, that is, disc, is divided into a plurality ofallocation extents having variable lengths. Each of the allocationextents is composed of a plurality of blocks having a fixed length. Eachof the blocks is composed of a predetermined number of physical sectors.

[0046]FIG. 2 illustrates an anchor descriptor. Referring to FIG. 2, thedisc has four anchor descriptors arranged thereon. Each of the anchordescriptors has positions of management information areas for volumemanagement recorded thereon. A volume structure descriptor in themanagement information areas for volume management includes physicalvolume information, partition information, logical volume informationand a partition map.

[0047] The volume structure descriptor has a logical volume as a userarea described therein. The logical volume is illustrated in FIG. 3.Referring to FIG. 3, a file system descriptor is arranged in the logicalvolume. An MIA (Management Information Area) is disposed in theproximity of the top and the end of the logical volume. Each of the MIAsincludes a file table, an allocation extent table, an allocationstrategy table, a defect information table, and an extended attributetable. The lengths of the allocation extents are described in allocationstrategy records which form the allocation strategy table.

[0048] A user sets the lengths of allocation extents of data of a fileto be recorded onto a disc before the data are recorded onto the disc.This allows, for example, for AV data to be recorded in a format ofallocation extents of a comparatively large length and for PC data to berecorded in another format of allocation extents of a comparativelysmall length. Since AV data are in most cases continuous data, data canbe recorded and reproduced in a comparatively high efficiency where thelength of allocation extents is comparatively long.

[0049]FIG. 4 illustrates a procedure of setting the length of allocationextents. Referring to FIG. 4, in step S11, a drive unit 7 which will behereinafter described with reference to FIG. 19 records an allocationstrategy record corresponding to a set length of, allocation extentsinto the allocation strategy tables included in the MIAs. A plurality ofallocation strategy records can be written into the allocation strategytables. FIG. 5 shows an example of a screen to be used for a user to setthe length of allocation extents. For the length of allocation extents,an arbitrary length such as 4 MBytes or more, 64 KBytes, or 2 KBytes canbe selectively set. In this instance, a plurality of different lengthscan be set. The disc allows recording only in a designated one of theformats for allocation extents of the lengths set in this manner inadvance.

[0050] Processing when data are recorded onto a disc after a length ofallocation extents is set and recorded onto the disc proceeds in suchmanner as illustrated in a flow chart of FIG. 6. Referring to FIG. 6,first in step S21, a user will select a length of allocation extents ofdata to be recorded subsequently. FIG. 7 shows an example of a screen tobe used to select a length of allocation extents. For such length, onlyvalues set in advance to the disc are displayed. The user will manuallyoperate a button displayed on the screen to select a length ofallocation extents corresponding to the button. By designating a greaterlength for allocation extents when AV data are to be recorded than thatwhen PC data are to be recorded, recording of data of a comparativelyhigh efficiency is allowed. By the designation of a length forallocation extents, the allocation strategy record arranged in theallocation strategy tables is designated. After the designation iscompleted, the drive unit 7 records inputted data onto the disc in stepS22. After the recording of data is completed, the drive unit 7 records,in step 23, a number corresponding to the length of the allocationextents of the file onto the disc. A file management unit 6 which willbe hereinafter described with reference to FIG. 19 knows the numbercorresponding to the length of the allocation extents and can thereafterutilize contents of a corresponding one of allocation strategy records.

[0051] When a system control unit 5 which will be hereinafter describedwith reference to FIG. 19 can discriminate whether AV data are to berecorded or PC data are to be recorded, the processing in step S21described above may be performed without receiving an input from theuser.

[0052] A file is recorded onto the disc in such a manner as describedabove.

[0053] Now, a construction of a volume is described. The Disc Extent isused to represent an area aligned with an MIB (Management InformationBlock) in a descriptor recorded in the MIAs which will be hereinafterdescribed. The Disc Extent is recorded in such a form as illustrated inTable 1 below. TABLE 1 Desc Extent RBP Length Name Contents 0 2Offset(Number of MIB)from Uint16 top of a descriptor 2 2 Length(Numberof MIB) Uint16

[0054] The Offset from Top of a descriptor (RBP 0) designates an offset(MIB number) from the top MIB to the area of the descriptor. The Length(RBP 2) designates a magnitude (MIB number) of the area.

[0055] The PDL Entry (Primary Defect List Entry) is used to record aphysical sector size of a physical sector for which slipping isperformed in defect management. The PDL Entry is recorded in a formindicated in Table 2 below. TABLE 2 PDL Entry RBP Length Name Contents 04 Physical Sector Number of Uint32 Defect Sector

[0056] The Physical Sector Number of Defect Sector (RBP 0) designates aphysical sector number of a physical sector for which slipping isperformed.

[0057] The SDL Entry (Secondary Defect List Entry) is used to record thephysical sector number of a physical sector for which linear placementis performed in defect management and the physical sector number ofanother physical sector to be used as a substitute for the physicalsector. The SDL Entry is recorded in a form indicated in Table 3 below.TABLE 3 SDL Entry RBP Length Name Contents 0 4 Physical Sector Number ofUint32 Defect Sector 4 4 Physical Sector Number of Uint32 Spare Sector

[0058] The Physical Sector Number of Defect Sector of Table 3 abovedesignates the physical sector number of a physical sector for whichlinear replacement is performed. The Physical Sector Number of SpareSector (RBP 4) designates the physical sector number of a substitutephysical sector to be used in linear replacement.

[0059] The Anchor Points represents start points of volume structureanalyses. In the Anchor Points, an Anchor Descriptor is recorded. Thephysical sector number of a physical sector which makes an anchor pointis not prescribed.

[0060] However, in a VDR, the following prescriptions are used. Inparticular, in the case of a ROM (Read Only Memory) disc or a RAM(Random Access Memory) disc, Ch, 20h, LPSN (Last Physical SectorNumber)-20h, LPSN-Ch (any value having the suffix h represents that itis a hexadecimal number) are determined as anchor points. In the case ofa partial ROM disc, Ch, 20h, LPSN-20h and LPSN-Ch in ROM and RAM areasare determined as anchor points. In this instance, where appropriateinformation is recorded at the anchor points of the RAM area, theinformation is used, but where appropriate information is not recorded,the information in the ROM area is used.

[0061] An anchor descriptor is recorded in a physical sector, whichserves as an anchor point, beginning with the byte position 0. Themagnitude of the anchor descriptor is equal to or smaller than thephysical sector size. Further, the area from a byte next to the lastbyte of the descriptor to the last byte of the physical sector isreserved for possible extension in the future, and #00 is set to allbytes in the area. The anchor descriptor has recorded therein adefinition of a main MIA area and a definition of a reserve MIA area,positions of respective MIA maps and so forth.

[0062] Various pieces of information regarding a volume are recorded ina management information area (MIA) for volume management. In order tosecure the reliability, two MIAs having information of the same contentsare recorded at different locations on the physical volume, and areindividually referred to as main MIA and reserve MIA. A physical sectorin each MIA is called management information block (MIB) and an offsetof the physical sector number of a physical sector from the top MIB ofthe MIA is called management information block number (MIB number). Fordesignation of an MIB, the MIB number of it is used. Each MIA iscomposed of MIBs which cannot be used because of a defect or the like,unused MIBs, and MIBs used to record data of an MIA map for the main MIA(MIA Map for Main MIA), an MIA map for the reserve MIA (MIA Map forReserve MIA), a Volume Structure Descriptor, a Media InformationDescriptor, a Drive Information Descriptor and an Extended DataDescriptor.

[0063] For what object an MIB in an MIA is used is recorded in an MIAmap. Start positions and magnitudes of the main MIA and the reserve MIAand positions of the MIA maps in the MIAs are defined by an anchordescriptor.(The data mentioned above may be recorded in a single MIB orover a plurality of MIBs. Where the data are recorded over a pluralityof MIBs, in what order the MIBs are to be linked is recorded in a MapEntries field in the MIA map. When the data come to an endintermediately of an MIB, #00 is set to those bytes beginning with thebyte next to the end of the data and ending with the last byte of theMIB.

[0064] Subsequently, a partition is described. A data storage areadefined by Partition Information in the Volume Structure Descriptor iscalled partition. One physical volume can be divided into a plurality ofpartitions. A number for specifying a partition in the physical volumeis called partition number. The partition number is an integer whichmonotonously increases one by one beginning with 0. Physical sectors ina same partition have an equal physical sector size.

[0065] A partition is defined as a table of partition information in theVolume Structure Descriptor. The partition information defines thepartition with the physical sector number of a physical sector at thetop of the partition and the number of physical sectors which belong tothe partition. At least one or more partitions are defined in thephysical volume. The partition numbers are determined in an order inwhich the partition information is recorded in the Volume StructureDescriptor. The partition number of the partition defined by the firstpiece of partition information is 0, and that of the second partitionis 1. In this manner, the partition number increases one by one, andthat of the nth partition is n-1.

[0066] Subsequently, the Logical Volume is described. The Logical Volumerepresents a data storage area defined as an aggregate of partitions inthe logical volume information of the Volume Structure Descriptor. Thearea of the Logical Volume is formed from partition areas linked in anorder of description of the Partition Map of the logical volumeinformation. The Partition Map designates partitions belonging to thelogical volume with sets of the Volume Identifier which uniquely definesthe physical volume and partition numbers of the physical volume. TheLogical Volume may be composed of partitions which belong to differentphysical volumes, or a single partition may belong to a plurality ofLogical Volumes.

[0067] The logical volume is handled as a single area irrespective of abreakpoint between partitions or physical sectors, and contents of itare read and written in units of a logical sector. When the magnitude ofthe logical volume is not a multiple of the logical sector size, afragmental area which appears in the last physical sector is reservedfor future extension and is not used. The Volume Structure Descriptordescribes a definition of information regarding the partitions includedin the physical volume, a definition of the logical volumes and soforth. In order to define a logical volume which extends over aplurality of physical volumes, the logical volume information isdescribed in the Volume Structure Descriptor of that physical volume inwhich the partition of the partition number 0 is defined without fail.

[0068] It is to be noted that, in order to secure the reliability, thephysical volume information may be described in the Volume StructureDescriptor of the physical volume to which some other partition otherthan the partition of the partition number 0 belongs. The VolumeStructure Descriptor is recorded in the MIAs.

[0069] Subsequently, Defect management is described. Defect managementby slipping and linear replacement can be performed for each partition.Whether or not Defect management should be performed for each partitionis designated with the partition information of the Volume StructureDescriptor. A substitute data area to be used for slipping and linearreplacement is called spare area. In partitions which belong to the samelogical volume as that of a partition for which defect management is tobe performed, one or more spare areas are assured without fail. Further,when linear replacement is to be performed, the last part of thepartition area is used as a spare area.

[0070] When slipping is performed, a top portion of the spare areaassured at the last part of the partition area is used as a spare area.On the other hand, where linear replacement is to be performed, for thesubstitute data area, a spare area other than that spare area in apartition which includes a defect sector may be used only if it belongsto the same logical volume and belongs to the same physical volume.

[0071] Information regarding slipping and linear replacement is recordedin the Defect List Information of the Volume Structure Descriptor.Information regarding slipping is recorded in the Primary Defect Listwhile information regarding linear replacement is recorded in theSecondary Defect List.

[0072] The Media Information Descriptor, which is an area into whichinformation regarding media is to be recorded, is used to recordinformation regarding zones. The Drive Information Descriptor is an areainto which information regarding a drive (apparatus to be used forrecording and reproduction of data) is to be recorded. Where a fixeddrive is used, various pieces of information are recorded in the DriveInformation Descriptor.

[0073] The Extended Data Descriptor is used to record extensioninformation which cannot be fully recorded in the physical volumeinformation, partition information and logical volume information.

[0074] Now, the volume data structure is described. The AnchorDescriptor has a magnitude smaller than the physical sector size and isrecorded in a format indicated in Table 4 below. TABLE 4 AnchorDescriptor BP Length Name Contents  0 8 Signature Signature  8 4 StartPhysical Sector Number of Uint32 Main MIA 12 4 Number of PhysicalSectors in Uint32 Main MIA 16 4 Start Physical Sector Number of Uint32Reserve 20 4 MIA Uint32 24 2 Number of Physical Sectors in Uint16Reserve MIA 26 2 Number of MIBs for MIA Map in Uint16 Main MIA(=x₁) 282x₁ Number of MIBs for MIA Map in Uint16 Reserve MIA(=x₂) 28+2x₁ 2x₂ MIBNumber of MIA Map for Uint16 Main MIA in Main MIA 28+2x₁+2x₂ 2x₁ MIBNumber of MIA Map for Uint16 Reserve MIA in Main MIA 28+4x₁+2x₂ 2x₂ MIBNumber of MIA Map for Uint16 Main MIA in Reserve MIA MIB Number of MIAMap for Reserve MIA in Reserve MIA

[0075] The data type field of the Signature (BP 0) has 16 set therein.The Start Physical Sector Number of Main MIA (BP 8) designates thephysical sector number of the physical sector at the top of the mainMIA. The Number of Physical Sectors in Main MIA (BP 12) designates thenumber of physical sectors of the main MIA. The Start Physical SectorNumber of Reserve MIA (BP 16) designates the physical sector number ofthe physical sector at the top of the reserve MIA. The Number ofPhysical Sectors in Reserve MIA (BP 20) designates the number ofphysical sectors of the reserve MIA. The Number of MIBs for MIA Map inMain MIA (BP 24) designates the magnitude (number of MIBs) of the MIAmap. The MIA numbers of MIBs for Main Map in Reserve MIA (BP 26)designates the magnitude (number of MIBs) of the reserve MIA. The MIBNumbers of MIA Map for Main MIA in Main MIA (BP 28) designates MIBs inthe main MIA in which the MIA map for the main MIA is recorded. The MIBnumbers of the MIBs which form the MIA map are set in order.

[0076] The MIB numbers of MIA Map for Reserve MIA in Main MIA (BP28+2x₁) designates the MIBs in the main MIA in which the MIA map for thereserve MIA is recorded. The MIB numbers of the MIBs which form the MIAmap are set in order. The MIB Numbers of MIA Map for Main MIA in ReserveMIA (BP 28+2x₁+2x₂) designates the MIBs in the reserve MIA in which theMIA map for the main MIA is recorded. The MIB Numbers of the MIBs whichform the MIA map are set in order. The MIB Numbers of MIA Map forReserve MIA in Reserve MIA (BP 28+4x₁+2x₂) designates the MIBs in thereserve MIA in which the MIA map for the reserve MIA is recorded. TheMIB Numbers of the MIBs which form the MIA map are set in order.

[0077] The MIA map is used to indicate a situation in use of the MIBs.The MIA map indicates the positions of MIBs which are used for recordingof various data, MIBs which cannot be used because of a defect or thelike, and MIBs which are not used. The MIA map is recorded in such aform as indicated in Table 5 below. TABLE 5 MIA Map BP Length NameContents  0 8 Signature Signature  8 2 Location of MIA Map Uint16 10 2Location of Volume Structure Descriptor Uint16 12 2 Location ofMediaInformation Descriptor Uinit16 14 2 Location of DriveInformationDescriptor Uint16 16 2 Location of Extended Data Descriptor Uint16 18 2Number of Map Entries(=x₁) Uint16 20 2x₁ Map Entries bytes

[0078] The data type field of the Signature (BP 0) has 2 set therein.The Location of MIA Map (BP 8) designates the MIB number of the top MIBof the MIA map. The Location of Volume Structure Descriptor (BP 10)designates the MIB number of the top MIB of the Volume StructureDescriptor. The Location of Media Information Descriptor (BP 12)designates the MIB number of the top MIB of the Media InformationDescriptor. The Location of Drive Information Descriptor (BP 14)designates the MIB number of the top MIB of the Drive InformationDescriptor.

[0079] The Location of Extended Data Descriptor (BP 16) designates theMIB number of the top MIB of the Extended Data Descriptor. The Number ofMap Entries (BP 18) designates the number of entries of the Map Entrybeginning with BP 20. This number is equal to the number of MIBsinvolved in the MIA and is equal to or smaller than #FFF0. The MapEntries (BP 20) designates the situation of use of the MIBs. One MapEntry is composed of Uint16, and the first map entry corresponds to thefirst MIB, the second map entry to the second MIB, . . . , and the nthmap entry to the nth MIB. Table 6 below indicates the values of the mapentries. TABLE 6 MIA Map Entry Value Interpretation #0000-#FFEF Next MIBNumber #FFF0 Unusable MIB #FFF1 Unused MIB #FFF2-#FFFE Reserved #FFFFLast MIB of the data structure

[0080]FIG. 8 is a view illustrating a structure of the Volume StructureDescriptor. Referring to FIG. 8, the @APS indicates the Align toPhysical Sector, and data of the same indicates alignment to a physicalsector. Upon such alignment, #00 is placed into an area from a byte nextto the location at which data to be recorded immediately precedently isactually recorded to the end of the sector.

[0081] The Volume Structure Descriptor Header is recorded in accordancewith Table 7 below. TABLE 7 Volume Structure Descriptor Header BP LengthName Contents  0 8 Signature Signature  8 2 Descriptor Size Uint16 10 2Reserved #00 bytes 12 4 Offset to Physical Volume Information Uint32(=48) 16 4 Offset to Partition Information(=416) Uint32 20 4 Offset toSpare Area Information Uint32 24 4 Offset to Logical Volume InformationUint32 28 4 Offset to Defect List Information Uint32

[0082] In the data type field of the Signature (BP 0), 17 is set. TheDescriptor Size (BP 8) designates the magnitude (number of MIBs) of theVolume Structure Descriptor. The Reserved (BP 10) is reserved for futureextension and has #00 set to all bytes thereof. The Offset to PhysicalVolume Information (RPB 12) designates an offset (byte number) of thePhysical Volume Information from the top byte of the Volume StructureDescriptor and has 48 set therein. The Offset to Partition Information(RBP 16) designates an offset (byte number) of the Partition Informationfrom the top byte of the Volume Structure Descriptor, and has 416 settherein. The Offset to Spare Area Information (RBP 20) designates anoffset (byte number) of the Spare Area Information from the top byte ofthe Volume Structure Descriptor. The Offset to Logical VolumeInformation (RBP 24) designates an offset (byte number) of the LogicalVolume Information from the top byte of the Volume Structure Descriptor.The Offset to Defect List Information (RBP 28) designates an offset(byte number) of the Defect List Information from the top byte of theVolume Structure Descriptor.

[0083] The Physical Volume Information must be recorded in accordancewith Table 8 below. TABLE 8 Physical Volume Information RBP Length NameContents  0  2 Character Set Character set  2  2 Physical Volume NameSize Uint16  4 256 Physical Volume Name bytes 260  20 Physical VolumeIdentifier bytes 280  6 Creation Time Times Stamp 286  6 ModificationTime Times Stamp 292  2 Number of Partitions(=Np) Uint16 294  2 Numberof Spare Areas(=Ns) Uint16 296  2 Number of Partitions with DefectUint16 Management(=Nadump) 298  2 Number of Logical Volume (=Nv) Uint16300  2 Reserved #00 bytes 302  2 Extended Data Identifier Uint16 bytes304  64 Extended Data bytes

[0084] The Character Set (RBP 0) designates a character code of the nameof a physical volume recorded in the Physical Volume Name field. ThePhysical Volume Name Size (RBGP 2) designates the magnitude (bytenumber) of the name of the physical volume recorded in the PhysicalVolume Name field. The Physical Volume Name (RBP 4) designates the nameof the Physical Volume. The Physical Volume Identifier (RBP 260)designates a byte train for specifying the Physical Volume uniquely forpractical use. The Creation Time (RBP 280) designates a date and timewhen the Volume Structure of the Physical Volume was defined for thefirst time. The Modification Time (RBP 286) designates the latest dateand time when the Volume Structure of the Physical Volume was modified.The Number of Partitions (RBP 292) designates the number of partitionsincluded in the Physical Volume and is equal to the number of pieces ofthe partition information.

[0085] The Number of Spare Areas (RBP 294) designates the number ofspare areas included in the Physical Volume and is equal to the numberof pieces of the spare area information. The Number of Partitions withDefect Management (RBP 296) designates the number of those partitionsincluded in the Physical Volume for which defect management is to beperformed, and is equal to the number of the Defect List. The Number ofLogical Volumes (RBP 298) designates the number of logical volumes towhich the partitions included in the Physical Volume belong, and isequal to the number of pieces of the physical volume information. TheReserved (RBP 300) is reserved for future extension and has #00 set toall bytes therein. The Extended Data Identifier (RBP 302) designates anID for specifying extended data recorded in the extended data area. TheExtended Data (RBP 304) is reserved for future extension and has #00 setto all bytes therein.

[0086] The Partition Information must be recorded in a form indicated inTable 9 below. TABLE 9 Partition Information RBP Length Name Contents  0 4 Start Physical Sector Number Uint32  4  4 Number of Physical SectorsUint16  8  4 Number of Usable Sectors Uint16 12  4 Physical Sectorsize(=PSS) Uint16 16  1 Access Type Uint8 17  1 Usage Information Uint818  2 Reserved #00 bytes 20  4 Location of Primary Defect ListDescExtent 24  4 Location of secondary Defect List DescExtent 28  2Reserved #00 bytes 30  2 Extended Data Identifier Uint16 32 64 ExtendedData #00 bytes

[0087] The Start Physical Sector Number (RBP 0) designates the physicalsector number of the top physical sector in an area which forms thepartition. The Number of Physical Sectors (RBP 4) designates the numberof physical sectors of the area which forms the partition. The Number ofUsable Sectors (RBP 8) designates the total number of those physicalsectors in the area forming the partition which can be used, and isequal to the number of those physical sectors in an area except spareareas included in the area of the partition from the total area of thepartition. The Physical Sector Size (RBP 12) designates the magnitude(number of bytes) of the physical sector of the area which forms thepartition. The Access Type (RBP 16) designates a state of a recordingcharacteristic of the partition. Table 10 below indicates contents ofthe access type. TABLE 10 Access Type Value Name Interpretation 0 ReadOnly The user may not write any data in this partition 1 Write Once Theuser can write data but once in this partition 2 Rewritable The user canwrite data many times in this partition 3-15 Reserved Reserved forfuturer use

[0088] The Usage Information (RBP 17) designates a state of use of thepartition. Table 11 below indicates contents of the Usage Information.TABLE 11 Usage information Bit Interpretation 0 Used(1:used,0:not used)1 Defect management:Slipping(1:on,0:off) 2 Defect management:Linearreplacement(1:on,0:off) 3-7 Reserved

[0089] The Reserved (RBP 18) is reserved for future extension and has#00 set to all bytes therein. The Location of Primary Defect List (RBP20) stores in the field thereof information regarding the position atwhich the primary defect list is recorded when defect management byslipping is to be performed for the partition, but sets #00 to all bytestherein when defect management by slipping is not to be performed. TheLocation of Secondary Defect List (RBP 24) stores in the field thereofinformation regarding the position at which the secondary defect list isrecorded when defect management by linear replacement is to be performedfor the partition, but sets #00 to all bytes therein when defectmanagement by linear replacement is not to be performed. The Reserved(RPB 28) is reserved for future extension and has #00 set to all bytestherein. The Extended Data Identifier (RBP 30) designates an ID forspecifying extended data recorded in the Extended Data field or theextended data area. The Extended Data (RBP 32) are reserved for futureextension and has #00 set to all bytes therein.

[0090] The Spare Area Information is recorded in a form indicated inTable 12 below. TABLE 12 Spare Area Information RBP Length Name Contents0 4 Start Physical Sector Number Uint16 4 4 Number of Physical SectorUint16 8 8 Reserved #00 bytes

[0091] The Stare Physical Sector Number (RBP 0) designates the physicalsector number of the top physical sector of the spare area. The Numberof Physical Sector (RBP 4) designates the number of physical sectorswhich form the spare area. The Reserved (RBP 8) is reserved for futureextension and has #00 set to all bytes therein.

[0092] The Logical Volume Information Header is recorded in a formindicated in Table 13 below. TABLE 13 Logical Volume Information HeaderRBP Length Name Contents  0  2 Character Set Character Set  2  2 LogicalVolume Name Size Uint16  4 256 Logical Volume Name bytes 260  2 BootIndicator Uint16 262  2 File System Indicator Uint16 264  2 LogicalSector Size Uint16 266  2 Number of Partitions(=Npv) Uint16 268  4Reserved #00 bytes 272  16 Logical Volume Contents Use bytes 288  14Reserved #00 bytes 302  2 Extended Data Identifier Uint16 304  64Extended Data #00 bytes

[0093] The Character Set (RBP 0) designates a character code of the nameof the logical volume recorded in the Logical Volume Name field. TheLogical Volume Name Size (RBP 2) designates the magnitude (byte number)of the name of the logical volume designated in the Logical Volume NameField. The Boot Indicator (RBP 260) designates information regardingstarting from the logical volume. Contents of the Boot Indicator areindicated in Table 14 below. The physical volume must not include two ormore logical volumes whose boot indicators are active and whose toppartitions are in the physical volume. TABLE 14 Boot Indicator ValueName Contents 00h Not Active Physical volume is not set that computerboots up from this logical volume 80h Active Physical volume is set thatcomputer boots up from this logical volume

[0094] The File System Indicator (RBP 262) designates a file system usedin the logical volume. Contents of the File System Indicator areindicated in Table 15 below. TABLE 15 File System Indicator Value NameContents 00h Unknown This logical volume is unknown. 01h 12bit FAT Thislogical volume is formatted with 12bit FAT. 04h 16bit FAT This logicalvolume is formatted with 16bit FAT. 05h 16bit FAT, This logical volumeis formatted with 16bit FAT, Extended and defined an extended partition.06h 16bit FAT, This logical volume is formatted with 16bit FAT,Extended, and defined an extended partition,using 64KB/ 64KB/clasterclaster. 07h HPFS This logical volume is formatted with HPFS. 0Bh 32bitFAT This logical volume is formatted with 32bit FAT. F0h KIFS Thislogical volume is formatted with KIFS.

[0095] The Logical Sector Size (RBP 264) designates the magnitude (bytenumber) of the logical sector of the logical volume. The Number ofPartitions (RBP 266) designates the number of partitions which form thelogical volume, and is equal to the number of the partition map. TheReserved (RBP 268) is reserved for future extension and has #00 set toall bytes therein. The Logical Volume Contents Use (RBP 272) is an areawhich may be used freely by the file system used by the logical volume.The reserved (RBP 288) is reserved for future extension and has #00 setto all bytes therein. The Extended Data Identifier (RBP 302) designatesan ID for specifying extended data recorded in the Extended Data area.The Extended Data (RBP 304) is reserved for future extension and has #00set to all bytes therein.

[0096] The Partition Map is recorded in a form indicated in Table 16below. TABLE 16 Partition Map RBP Length Name Contents 0 20 VolumeIdentifier bytes 20 2 Partition Number Uint16 22 2 Reserved #00 bytes

[0097] The Volume Identifier (RBP 0) designates a physical volumeidentifier recorded in the Physical Volume Information of the physicalvolume to which the partition which forms the logical volume belongs.The Partition Number (RBP 20) designates the partition number of thepartitions which form the logical volume. The Reserved (RBP 22) isreserved for future extension and has #00 set to all bytes therein.

[0098] The Defect List Information Header is recorded in a formindicated in Table 17 below. TABLE 17 Detect List Information Header RBPLength Name Contents 0 2 Number of MIB Primary Defect List Uint16 2 2Number of MIB for Secondary Defect List Uint16 4 12 Reserved #00 bytes

[0099] The Number of MIB for Primary Defect List (RBP 0) designates thenumber of MIBs used to record the primary defect list. The Number of MIBfor Secondary Defect List (RBP 2) designates the number of MIBs used torecord the secondary defect list. The Reserved is reserved for futureextension and has #00 set to all bytes therein.

[0100] The Primary Defect List/Secondary Defect List is recorded in aform indicated in Table 18 below. TABLE 18 Primary Defect List/SecondaryDefect List RBP Length Name Contents 0 8 Signature Signature 8 2Partition Number Uint16 10 2 Number of Entries(=Npd) Uint16 12 4Reserved #00 bytes 16 4(8)Npd Defect List Entry bytes

[0101] The data type field of the Signature (BP 0) has 18 set thereinfor the primary defect list, but has 19 set therein for the secondarydefect list. The Partition Number (BP 8) designates the partition numberof a partition in which the defect list is used. The Number of Entries(BP 10) designates the entry number of the Defect List Entry. TheReserved (RBP 12) is reserved for future extension and has #00 set toall bytes therein. The Defect List Entry (RBP 16) has, for the primarydefect list, the primary defect list entry recorded therein, but has,for the secondary defect list, the secondary defect list entry recordedtherein. The defect list entries in both cases are recorded in theascending order of values of the Physical Sector Number of Defect Sectorfields of the individual entries.

[0102] The structure of the Media Information Descriptor is illustratedin FIG. 9.

[0103] Referring to FIG. 9, the Media Information Descriptor Header isrecorded in a form indicated in Table 19 below. TABLE 19 Mediainformation Descriptor Header RBP Length Name Contents 0 8 SignatureSignature 8 2 Descriptor Size Uint16 10 6 Reserved #00 bytes 16 2 Numberof discs Uint16 18 2 Number of sides per disc Uint16 20 2 Number oflayers per side Uint16 22 2 Number of zones per layer(=Nz) Uint16 24 8Reserved #00 bytes 32 2 Number of cylinders Uint16 34 2 Number ofheads(tracks per cylinder) Uint16 36 2 Number of sectors per tracksUint16 38 10 Reserved #00 bytes

[0104] The data type field of the Signature (BP 0) has 20 set therein.The Descriptor Size (BP 8) designates the magnitude (MIB number) of theMedia Information Descriptor. The Reserved (BP 10) is reserved forfuture extension and has #00 set to all bytes therein. The Number ofdiscs (BP 16) designates the number of discs. The Number of sides perdisc (BP 18) designates the number of sides per disc. The Number oflayers per side (BP 20) designates the number of layers per side. TheNumber of zones per layer (BP 22) designates the number of zones perlayer. The Reserved (BP 24) is reserved for future extension and has #00set to all bytes therein. The Number of cylinders (BP 32) designates thenumber of cylinders. The Number of heads (tracks per cylinder) (BP 34)designates the number of heads (number of tracks per cylinder). TheNumber of sectors per tracks (BP 36) designates the number of sectorsper track. The Reserved (BP 38) is reserved for future extension and has#00 set to all bytes therein.

[0105] The Zone Information is recorded in a form indicated in Table 20below. TABLE 20 Zone Information RBP Length Name Contents 0 4 StartPhysical Sector Number Uint16 4 4 Number of Physical Sector Uint16 8 8Reserved #00 bytes

[0106] The Start Physical Sector Number (RBP 0) designates the physicalsector number of the top physical sector of the zone. The Number ofPhysical Sector (RBP 4) designates the number of physical sectors whichcompose the zone. The Reserved is reserved for future extension and has#00 set to all bytes therein.

[0107] The structure of the Drive Information Descriptor is illustratedin FIG. 10.

[0108] Referring to FIG. 10, the Drive Information Descriptor Header isrecorded in a form indicated in Table 21 below. TABLE 21 DriveInformation Descriptor Header BP Length Name Contents 0 8 SignatureSignature 8 2 Descriptor Size Uint16 10 1 Strategy Type Uint8 11 5Reserved #00 bytes

[0109] The data type field of the Signature (BP 0) has 21 set therein.The Descriptor Size (BP 8) designates the magnitude (MIB number) of theDrive Information Descriptor. The Strategy Type (BP 10) designates astrategy type. The Reserved is reserved for future extension and has #00set to all bytes therein.

[0110] The structure of the Extended Data Descriptor is illustrated inFIG. 11. Referring to FIG. 11, the @APS represents Align to PhysicalSector and indicates that the pertaining data must be aligned with thephysical sector. Further, the area beginning with a byte next to thelast data and ending with the end of the sector has #00 set therein.

[0111] The Extended Data Descriptor Header is recorded in a formindicated in Table 22 below. TABLE 22 Extended Descriptor Header BPLength Name Contents 0 8 Signature Signature 8 2 Descriptor Size Uint1610 6 Reserved #00 bytes 16 2 Location of Extended Data for Physical DescExtent Volume 20 4Np Location of Extended Data for Desc ExtentPartitions 20+4Np 4Nv Location of Extended Data for Logical Desc ExtentVolume

[0112] The data type field of the Signature (BP 0) has 22 set therein.The Descriptor Size (BP 8) designates the magnitude (MIB number) of theExtended Data Descriptor. The Reserved is reserved for future extensionand has #00 set to all bytes therein. The Location of Extended Data forPhysical Volume (BP 16) designates a location in which extended dataregarding the physical volume is recorded. The Location of Extended Datafor Partitions (BP 20) designates a location in which extended dataregarding the partitions are recorded. The Location of Extended Data forLogical Volume (BP 20+4Np) designates a location in which extended dataregarding the logical volumes are recorded.

[0113] Subsequently, levels of medium interchange are described. Thelevel 0 of medium interchange has the following limitations. Inparticular, a logical volume is composed of partitions which belong tothe same physical volume. Where a plurality of partitions are defined inthe same physical volume, the areas of the partitions must not overlapwith each other. All of physical sectors of the partitions which composethe logical volume have an equal physical sector size. The logicalsector size is a multiple of the physical sector size, or alternatively,the physical sector size is a multiple of the logical sector size. Themagnitude of the partitions is a multiple of a value of a larger one ofthe logical sector size and the physical sector size. A partition forwhich defect management is to be performed assures one or more spareareas therein without fail. Defect management by linear replacement usesthe spare area or areas assured in the partition as a substitute dataarea.

[0114] The level 1 of medium interchange has no limitation.

[0115] Subsequently, an Example of the volume structure is described.Table 23 below illustrates a table of an example of the volume structureof a hybrid disc of FAT, IS09660 (with Joliet), ISO/IEC13346, KIFS for aVDR. The mark ♦ represents position fixed information which cannot bere-arranged. TABLE 23 Example of volume structure (FAT,9660,13346,KIFSHybrid) PSN(hax) Descriptor Contents 0 [FAT]Partition Table[FAT]Partition Table — — — c [KIFS]Anchor Descriptor [KIFS]Anchor — — —10 [9660]Primary Volume Descriptor [9660/13346/KIFS] 11 [9660]PrimaryVolume Descriptor Volume recognition (Reserve) Sequence 12[9660]Supplementary Volume Descriptor(for Joliet) 13 [9660]VolumeDescriptor Set Terminator 14 [13346]Beginning Extended Area Descriptor15 [13346]NSR Descriptor 16 [13346]Terminating Extended Area Descriptor17 [13346]Beginning Extended Area Descriptor 18 [KIFS]KIFS Descriptor 19[13346]Terminating Extended Area Descriptor — — — 30 [13346]PrimaryVolume Descriptor [13346]Main 31 [13346]Implementation Use Volume VolumeDescriptor Descriptor Sequence 32 [13346]Partition Descriptor Extent 33[13346]Logical Volume Descriptor 34 [13346]Unallocated Space Descriptor35 [13346]Terminating Descriptor — — — 40 [13346]Primary VolumeDescriptor [13346]Reserve 41 [13346]Implementation Use Volume VolumeDescriptor Descriptor Sequence 42 [13346]Partition Descriptor Extent 43[13346]Logical Volume Descriptor 44 [13346]Unallocated Space Descriptor— — 80 [KIFS]MIA Map for Main MIA [KIFS]Main MIA 81 [KIFS]MIA Map forReserved MIA 82 [KIFS]Volume Structure Descriptor 83 [KIFS] PrimaryDefect List 84 [KIFS] Secondary Defect List 85 [KIFS]Media InformationDescriptor 86 [KIFS]Drive Information Descriptor 87 [KIFS]Extended DataDescriptor 88 [KIFS] Extended Data — — — C0 [KIFS]MIA Map for ReserveMIA [KIFS]Reserve MIA C1 [KIFS]MIA Map for Main MIA C2 [KIFS]VolumeStructure Descriptor C3 [KIFS] Primary Defect List C4 [KIFS] SecondaryDefect List C5 [KIFS] Defect Sector C6 [KIFS]Media InformationDescriptor C7 [KIFS]Drive Information Descriptor C8 [KIFS]Extended DataDescriptor C9 [KIFS] Extended Data — — — 100 [13346]Anchor VolumeDescriptor [13346] Anchor Pointer — — — 150 [KIFS]LOGICAL VOLUME — —LPSN-150 — — — — — LPSN-100 [13346]Anchor Volume Descriptor[13346]Anchor Pointer — — — LPSN-20 [13346]Anchor Descriptor[KIFS]Anchor — — — LPSN-C [13346]Anchor Descriptor [KIFS]Anchor — — —LPSN [13346]Anchor Volume Descriptor [13346]Anchor Pointer

[0116] Subsequently, an AV File System constructed on the logical volumewill be described. The Logical Sector Number is a number applied toidentify a logical sector. The Logical Volume is an aggregate composedof logical sectors having an equal size and having successive logicalsector numbers of an ascending order beginning with 0.

[0117] The Management Information Area (MIA) for file system managementis an area including a plurality of successive logical sectors on thelogical volume for storing various control information of the AV filesystem. The Management Information Block (MIB) is a logical sector inthe MIA. The Management Information Block Number (MIB Number) has avalue equal to a difference of the logical sector number of themanagement information block and the logical sector number of the topmanagement information block of the MIA.

[0118] In the following, the entire AV file system is described. The AVFile System Descriptor which will be hereinafter described is recordedin one logical sector and designates the positions and the magnitudes ofthe main MIA and the reserve MIA on the logical volume and the positionsof the MIA maps on the main MIA and the reserve MIA. The position of theAV File System Descriptor is set in the Logical Volume Contents Use (BP284) field of the Logical Volume Information Header describedhereinabove in such a manner as seen from Table 24 below. TABLE 24Logical Volume Contents Use field RBP Length Name Contents 0 4 Main AVFile System Descriptor Uint32 Location 4 4 Reserve AV File SystemDescriptor Uint32 Location 8 8 Reserved #00 bytes

[0119] The Main AV File System Descriptor Location (RBP 0) designatesthe logical sector number of the AV File System Descriptor. The ReserveAV File System Descriptor Location (RBP 4) designates the logical sectornumber of the AV File System Descriptor which is located at a locationdifferent from that designated by the Main AV File System DescriptorLocation. If only one AV file system descriptor is present on thelogical volume, then #FFFFFFFF is placed in the Reserve AV File SystemDescriptor Location. The Reserved (RBP 8) is reserved for futureextension and has #00 set therein.

[0120] Various management information of the AV file system is recordedin the Management Information Area (MIA) for file system management. Inorder to secure the reliability, two MIAs having management informationof the same contents are recorded at different locations on the logicalvolume and are individually called main MIA and reserve MIA. Thepositions and the magnitudes of the main MIA and the reserve MIA and thepositions of the MIA maps in the MIAs are defined by the AV File SystemDescriptor. A logical sector in the MIAs is called managementinformation block (MIB), and the offset of the logical sector number ofa management information block (MIB) from the top MIB of the MIA iscalled management information block number (MIB number).

[0121] For designation of an MIB, an MIB number is used. Each MIA is astructure of MIBs which cannot be used because of a defect or the like,unused MIBs, and MIBs for storing the MIA Map, File Table, AllocationExtents Table, Allocation Strategy Table, Defect Information Table(Optional) and Extended Attribute Table (Optional) which are datastructures. For what object each MIB in each MIA is used is recorded inthe MIA map. The various data structures are stored in one MIB or aplurality of MIBs. Where the data structures are recorded in a pluralityof MIBs, in what order the MIBs should be linked is recorded in the MapEntry field in the MIA map. If a data structure comes to an endintermediately in an MIB, then #00 is placed in bytes of the MIBbeginning with a byte next to the end of the data and ending with thelast byte of the MIB.

[0122] In the AV file system, files and directories are managed with afile table which will be hereinafter described. The structure of thefile table is determined depending upon the File Table Structure Typewhich is a parameter in the file table header. In the file tablestructure type 0, the file table is composed of a file table header andone or more file records. A file record is a data area of a fixed lengthand is composed of a field for identifying the file record, a field fordesignating a type of the file record, a field for designating dates andtimes of production and modification, a field for designating a positionand a magnitude of data, a field for designating an attribute, a fieldfor designating a parent file record called Parent Link, a field fordesignating a brother file record called Next Link, a field fordesignating a child file record called Child Link, and a field fordesignating an Extended Attribute Record Chain. A number called filerecord number is applied to a file record, and the parent link, nextlink or child link is designated using such file record number.

[0123] In the file table structure type 0, such a tree structure asshown in FIG. 12 wherein the first file record of the file table servesas a root is constructed. Referring to FIG. 12, each circle represents afile record, and the file record of the root is called Root File Record.Each file record which does not have data to be referred to is calleddirectory, and each file which has data is called file. Not only adirectory, but also a file can have a child file record. Thehierarchical structure just described is implemented by setting ChildLinks, Next Links and Parent Links as illustrated in FIG. 13.

[0124] A list of file records composed of Next Links is called filerecord chain and must not include two or more records which have a samefile type. A sub file is a kind of file and indicates part of data whichis referred to by a parent file record as if it were a separate file. Afile record wherein the value 10 is placed in the Data Location type ofthe Attribute field represents a sub file.

[0125] In the AV file system, management of data is performed in unitsof successive areas on a logical volume called Allocation Extent. TheAllocation Extent begins with an arbitrary byte offset of a logicalsector and either ends with another arbitrary byte offset in the logicalsector or includes succeeding zero or more logical sector or sectors andends with an arbitrary byte offset of another logical sector followingthe logical sector or sectors. The start point, end point, attribute andso forth of the Allocation Extent “t” are recorded in the AllocationExtent Record in the Allocation Extent Table.

[0126] The Allocation Extent Table has recorded therein allocationextent records which correspond to all allocation extents on the logicalvolume. Each allocation extent record has a field which indicates a nextallocation extent record, and a list including a plurality of allocationextent records can be produced using the field. This list is calledallocation extent record chain. Normally, file data are handled as asequenced set of allocation extents corresponding to an allocationextent record chain.

[0127] A list composed of those allocation extent records in anallocation extent table which are not used (records whose allocationextent record status is 00) is called free allocation extent recordchain and can be traced simply from the allocation extent table.Meanwhile, a list composed of those allocation extent records each ofwhich is determined not to be recommended for re-utilization since itincludes a defect in the corresponding allocation extent (those recordswhose allocation extent record status has the value of 10) is calleddefective allocation extent record chain. Also this list can be tracedsimply from the allocation extent table.

[0128] At which position an allocation extent is placed in a logicalvolume is determined by the Allocation Strategy. The allocation strategytable can register a plurality of allocation strategies therein andarrange an allocation extent on a logical volume using an allocationstrategy different for each file. The range of an area managed by eachallocation strategy or a parameter to be used by the allocation strategytable is recorded in an allocation strategy record in the allocationstrategy table. In the file table structure type 0, an allocationstrategy is determined for each file record and is recorded in the datalocation field of the file record. The data location field is referredto upon operation of the allocation extent so that a correspondingallocation strategy is recalled.

[0129] Two allocation strategy types of the Allocation Strategy Type 0and the Allocation Strategy Type 1 are defined. The Allocation StrategyType 0 is a type suitable to discontinuously handle files ofcomparatively small sizes such as index data while the AllocationStrategy Type 1 is a type suitable to continuously read or write data ofthe MPEG or the like.

[0130] The Defect Information Table is a table in which logical sectornumbers of defect sectors in the logical volume are recorded, and can beused for management of the defective sectors.

[0131] The Extended Attribute Table can be used to hold an extensionattribute of a file or a directory in the MIAs. The Extended AttributeTable is composed of an extended attribute table header and one or moreextended attribute table records. An extended attribute record is arecord of a fixed length having a field for a link, and an extendedattribute record chain which is a list of a plurality of extendedattribute records can be produced.

[0132] At the top of the data structure to be used by the AV filesystem, the Signature is set. The Signature is recorded in such a manneras seen in Table 25 below. TABLE 25 Signature RBP Length Name Contents 04 Identification bytes=“AVFS” 4 1 Version Uint8=1 5 1 Data type Uint8 62 Reserved #00 bytes

[0133] The Identification (RBP 0) has a character train “AVFS” settherein in accordance with the ISO/IEC 646. The Version (RBP 4)designates a version number and has 1 set therein. The Data type (RBP 5)designates a type of the data structure. Depending upon the type of thedata structure, one of values indicated in Table 26 below is placed inthe Data type. TABLE 26 Data type Value Interpretation 0 Reserved 1 AVFile System Descriptor 2 MIA Map 3 File Table 4 Allocation Extents Table5 Allocation Strategy Table 6 Defect Information Table 7 ExtendedAttribute Table 8-255 Reserved

[0134] The Reserved (RBP 6) is reserved for future extension and has #00set therein. The Signature is used to identify the data structure uponcrush recovery.

[0135] The AV File System Descriptor is recorded in such a manner asseen in Table 27 below. TABLE 27 AV File System Descriptor BP LengthName Contents 0 8 Signature Signature 8 4 Location of Main MIA Uint32 124 Location of Reserve MIA Uint32 16 2 Length of Main MIA Uint16 18 2Length of Reserve MIA Uint16 20 4 Creation Time Time Stamp 24 4Modification Time Time Stamp 28 2 Number of MIA Map Sectors in MainUint16 MIA(=x₁) 30 2 Number of MIA Map Sectors in Uint16 ReserveMIA(=x₂) 32 2x₁ MIA Map Sectors in Main MIA bytes 32+2x₁ 2x₁ MIA MapSectors in Reserve MIA bytes

[0136] The data type field of the Signature has 1 set therein. TheLocation of Main MIA (BP 8) designates the sector number of the startlogical sector of the main MIA. The Location of Reserve MIA (BP 12)designates the sector number of the start logical sector of the reserveMIA. The Length of Main MIA (BP 16) designates the size of the main MIAin the form of a logical sector number. The Length of Reserve MIA (BP18) designates the size of the reserve MIA in the form of a logicalsector number. The Creation Time (BP 20) stores the date and the timewhen the AV file system descriptor is produced. The Modification Time(BP 24) designates the date and the time when the AV file systemdescriptor is updated. The Number of MIA Map Sectors in Main MIA (BP 28)designates the number of MIB numbers described in the Main MIA MapSectors (BP 32).

[0137] The Number of MIA Map Sectors in Reserve MIA (BP 30) designatesthe number of MIB numbers described in the Reserve MIA Map Sectors (BP32+2x₁). The MIA Map Sectors in Main MIA (BP 32) designates MIBs whichform the MIA map in the main MIA, and the MIB numbers of the MIBs whichform the MIA map are set in order in the MIA Map Sectors in Main MIA.The MIA Map Sectors in Reserve MIA (BP 32+2x₁) designates MIBs whichform the MIA map in the reserve MIA, and the MIB numbers of the MIBswhich form the MIA map are set in order in the MIA Map Sectors inReserve MIA.

[0138] The MIA Map is used to indicate a situation of use of MIBs in theMIAs. The MIA Map indicates the positions of various data structures inthe MIAs, MIBs which cannot be used because of a defect, and unusedMIBs. The MIA Map is recorded in such a manner as seen in Table 28below. TABLE 28 MIA Map BP Length Name Contents 0 8 Signature Signature8 2 Location of MIA Map Uint16 10 2 Location of Allocation StrategyTable Uint16 12 2 Location of File Table Uint16 14 2 Location ofAllocation Extents Table Uint16 16 2 Location of Defect List TableUint16 18 2 Location of Extended Attribute Descriptor Uint16 20 2Reserved bytes 22 2 Number of Map Entries(=x₁) Uint16 24 2x₁ Map Entriesbytes

[0139] The data type field of the Signature (BP 0) is set to 2. TheLocation of MIA Map (BP 8) designates the MIB number of the top MIB ofthe MIA map in the MIA. The Location of Allocation Strategy Table (BP10) designates the MIB number of the top MIB of the Allocation StrategyTable in the MIA. The Location of File Table (BP 12) designates the MIBnumber of the top MIB of the file table in the MIA.

[0140] The Location of Allocation Extends Table (BP 14) designates theMIB number of the top MIB of the Allocation Extent Table in the MIA. TheLocation of Defect List Table (BP 16) designates the MIB number of thetop MIB of the Defect List Table in the MIA. If the MIA does not have adefect list table therein, then #FFFF is placed in the Location ofDefect List Table. The Location of Extended Attribute Descriptor (BP 18)designates the MIB number of the top MIB of the Extended AttributeDescriptor in the MIA. If the MIA does not have an extended attributedescriptor therein, then #FFFF is placed in the Location of ExtendedAttribute Descriptor. The Reserved (BP 20) is reserved for futureextension and has #00 set therein.

[0141] The Number of Map Entries (BP 22) designates the entry number ofmap entries beginning with (BP 24). The entry number is equal to thenumber of MIBs existing in the MIA and equal to or smaller than #FFF0.The Map Entries (BP 24) designates a situation of use of the MIBs in theMIA. One map entry is composed of Uint16, and the first map entrycorresponds to the first MIB of the MIA, the second map entrycorresponds to the second MIB, . . .

[0142] The value of the map entry has such meanings as indicated inTable 29 below. TABLE 29 Map entry value Value Interpretation#0000-#FFEF Next MIB Number #FFF0 Unusable MIB #FFF1 Unused MIB#FFF2-#FFFE Reserved #FFFF Last MIB of the data structure

[0143] If the data structure has a size equal to or smaller than thelogical sector size and is stored in one MIB, #FFFF is placed in the mapentry corresponding to the MIB. Where the data structure is recordedover a plurality of MIBs, in the map entry corresponding to each of theMIBs other than the last MIB, the MIB number of the next MIB is placed,but in the map entry corresponding to the last MIB, #FFFF is placed. AnyMIB whose map entry has the value #FFF1 indicates that the block isunused and can be used where the data structure requires a new MIB. AnyMIB whose map entry has the value #FFF0 indicates that the block is notsuitable for use (because it is a defective sector or the like).

[0144] The File Table is composed of a file table header and file tabledata as seen from FIG. 14. The structure of the file table data dependson the File Table Structure Type field of the file table header.

[0145] The File Table Header is recorded in such a manner as seen fromTable 30 below. TABLE 30 File Table Header BP Length Name Contents 0 8Signature Signature 8 4 Length of File Table Data Uint32 12 2 File TableStructure Type Uint16 14 18 File Table Structure Type bytes dependentinformation

[0146] The data type field of the Signature (BP 0) is set to 3. TheLength of File Table Data (BP 8) designates the length of the file tabledata in the form of a byte number. The File Table Structure Type (BP 12)defines the structure of the file table data. The File Table StructureType dependent Information (BP 14) is set to information determined foreach file table structure type.

[0147] Where the File Table Structure Type is 0, the file table iscomposed of a file table header and one or more file records as shown inFIG. 15. The file records have consecutive numbers of an ascending orderbeginning with 0, and such numbers are called file record numbers. Alist of the file records is produced by setting the file record numberof a next record in the Next Link field, and is called file recordchain. All of those file records in the file table which are not usedform a file record chain called free file record chain.

[0148] Where the file table structure type is 0, the File Table Headermust be recorded in such a manner as seen in Table 31 below. TABLE 31File Table Header BP Length Name Contents  0  8 Signature Signature  8 4 Length of File Table Data Uint32 12  2 File Table Structure TypeUint16(=0) 14  2 Number of File Records Uint16 16  2 First Free FileRecord Uint16 18 14 Reserved #00 bytes

[0149] The data type field of the Signature (BP 0) has 3 set therein.The Length of File Table Data (BP 8) is set to a number obtained bymultiplying a length of the file record by the Number of File Records(BP 14). The File Table Structure Type (BP 12) has 0 set therein. TheNumber of File Records (BP 14) designates the number of file recordswhich compose the file table. The file record number has a value equalto or higher than 1 but equal to or lower than #FFF0. The First FreeFile Records (BP 14) designates the first element of the free filerecord chain and has #FFFF set therein where the file table does notinclude any free file record. The Reserved (BP 18) is reserved forfuture extension and has #00 set therein.

[0150] The File Record must be recorded in such a manner as indicated inTable 32 below. TABLE 32 File Record of File Structure Type 0 RBP LengthName Contents  0 2 File ID Uint16  2 2 File Type Uint16  4 4 AttributeUint32  8 4 Creation Time Time Stamp 12 4 Modification Time Time Stamp16 8 Data Length Uint64 24 8 Data Location bytes 32 2 Child Link Uint1634 2 Next Link Uint16 36 2 Parent Link Uint16 38 2 Extended AttributeRecord Number Uint16

[0151] The File ID (RBP 0) designates a number for identifying a filerecord having a, same file type in the file record chain. The File Type(RBP 2) designates a number for indicating the type of the file record.The Attribute (RBP 4) designates the attribute of the file record ordata to be referred to by the file record. The Creation Time (RBP 8)designates the date and the time of production of the file record. TheModification Time (RBP 12) designates the date and the time ofmodification to the file record or to the data to be referred to by thefile record. The Data Length (RBP 16) designates the length of the datato be referred to by the Data Location (RBP 24) in units of a byte andhas 0 set therein where there is no data to be referred to. The DataLocation (RBP 24) designates the position of the data to be referred toby the file record. The interpretation of the field varies dependingupon contents of the Data Location Type (Bit 1-2) of the Attribute (RBP4). The Child Link (RBP 32) designates the file record number of thechild file record, and where no such file record is present, #FFFF isplaced in the Child Link. The Next Link (RBP 34) designates the filerecord number of a next file record which composes the file recordchain, and where the file record is the last element of the file recordchain, #FFFF is placed in the Next Link.

[0152] The Parent Link (RBP 36) designates the file record number of theparent file record, and where the file record is the root file record,the file record number of the file record itself, that is, 0, is placedin the Parent Link. The Extended Attribute Record Number (RBP 38)designates the number of the top extended attribute record of theextended attribute record chain used by the file record, and where theextended attribute record is not referred to, #FFFF is placed in theExtended Attribute Record Number.

[0153] The Attribute field is recorded in such a manner as illustratedin Table 33 below. TABLE 33 Attribute of the File Record BitInterpretation 0 Valid 1-2 Data Location Type 3 Protected 4 Sorted 5-31Reserved

[0154] The Valid (Bit 0) represents whether or not the file record isvalid, and where it is 0, this represents that the file record is notused and the file record is included in the free file record chain.Where the Valid is 1, this represents that the file record is used, andthe file record can be reached from the root file record through childlinks and next links. The Data Location Type (Bits 0-1) designates theformat of the Data Location (RBP 24). Where the Data Location Type is00, this represents that the data location has nothing to refer to (thevalue 00 is set where the file record is a directory). Where the datalocation type is 01, the data location is represented in a formatindicated in Table 34 below which includes the number of the topallocation extent record of the allocation extent record chain and theallocation strategy number. Where the Data Location Type is 10, thisrepresents that the file record is a sub file, and the data location isrepresented by Uint64 as an offset of the parent file record from thetop of data indicated by the data location. The Data Location Type 11 isreserved for future extension. TABLE 34 Data Location file of Type 01RBP Length Name Contents 0 2 Reserved #00 bytes 2 2 Allocation StrategyNumber Uint16 4 4 First Allocation Extent Record Number Uint32

[0155] The Protected (Bit 3) represents that the file record isprotected. The Sorted (Bit 4) represents that the file record chain towhich the file record belongs is sorted in an ascending order of thefile type and, in the same file type, sorted in an ascending order ofthe file ID. The Reserved (Bits 5-31) is reserved for future extension.

[0156] The Structure of the Allocation Extents Table is composed of anallocation extent table header and an allocation extent record orrecords as seen from FIG. 16. The allocation extent records are numberedconsecutively in an ascending order beginning with 0. The numbers arereferred to as allocation extent record numbers. By setting theallocation extent record number of the next record to the nextallocation extent record field, a list of the allocation extent recordsis produced. This list is referred to as allocation extent record chain.

[0157] The Allocation Extents Table Header is recorded in such a manneras indicated in Table 35 below. TABLE 35 Allocation Extents Table HeaderBP Length Name Contents  0 8 Signature Signature  8 4 Number ofAllocation Extent Records Uint32 12 4 First Free Allocation ExtentRecord Uint32 16 4 First Defective Allocation Extent Uint32 20 4Reserved #00 bytes

[0158] The data type field of the Signature (BP 0) has 4 set therein.The Number of Allocation Extent Records (BP 8) designates the number ofallocation extent records in the allocation extent table. The First FreeAllocation Extent Record (BP 12) designates the first element of thefree allocation extent record chain.

[0159] When the allocation extent table has no free allocation extentrecord, #FFFFFFFF is placed in this field. The First DefectiveAllocation Extent Record (BP 16) designates the first element of thedefective allocation extent record chain. When the allocation extenttable does not include a defective allocation extent record therein,#FFFFFFFF is placed in this field. The Reserved (BP 20) is reserved forfuture extension and has #00 set therein.

[0160] The Allocation Extent Record represents the start position, theend position and the attribute of the allocation extent and the positionof the next allocation extent record which forms the allocation extentrecord chain. The allocation extent record is recorded in such a manneras indicated in Table 36 below. TABLE 36 Allocation Extent Record RBPLength Name Contents  0 4 Start Logical Sector Number Uint32  4 1Allocation Strategy Number Uint8  5 1 Reserved Uint8  6 2 Start OffsetUint16  8 4 End Logical Sector Number Uint32 12 2 Reserved Uint16 14 2End offset Uint16 16 4 Attribute Uint32 20 4 Next Allocation ExtentRecord Uint32 24 8 Length of the Allocation Extent Uint64

[0161] The Start Logical Sector Number (RBP 0) designates a logicalsector which includes the start byte of the allocation extent, and has alogical sector number placed therein. The Allocation Strategy Number(RBP 4) designates in accordance with which allocation strategy theallocation extent record is arranged. The Reserved (RBP 5) is reservedfor future extension and has #00 set therein. The Start Offset (RBP 6)designates a byte offset from the top byte of the logical sectorincluding the start byte of the allocation extent to the start byte andhas 0 placed herein if the start position is equal to the top byte ofthe logical sector.

[0162] The End Logical Sector Number (RBP 8) designates the logicalsector number of the logical sector including the last byte of theallocation extent. The Reserved (RBP 12) is reserved for futureextension and has #00 set therein. The End Offset (RBP 14) designatesthe offset from the top byte of the logical sector including the endbyte of the allocation extent to the end byte and has 0 placed thereinif the end byte is equal to the top byte of the logical sector. Thevalue indicated by the Attribute (RBP 16) signifies such meaning asindicated in Table 37 below. TABLE 37 Attribute of the Allocation ExtentRecord Bit Interpretation 0-1 Allocation Extent Record Status 1-31Reserved

[0163] Where the allocation extent record status (Bits 0-1) is 01, thisallocation extent record indicates a valid allocation extent and allowsnormal readout. Where the bits are 11, this allocation extent recordindicates a valid allocation extent, but indicates that there is thepossibility that it may not allow normal readout because of presence ofa defect sector or the like. Where the bits are 00, this indicates thatthe allocation extent record is not used at present and can be used toarrange a new allocation extent. Where the bits are 10, this indicatesthat the allocation extent indicated by the allocation extent record isnot referred to at all, but it is not suitable to use it to arrange anew allocation extent because it includes a defect sector. The reserved(Bit 2-31) is reserved for future extension and has 0 set therein.

[0164] The Next Allocation Extend Record (RBP 20) designates the numberof the next allocation extent record which composes the allocationextent record chain. Where the allocation extent record is the lastelement of the allocation extent record chain, #FFFFFFFF is placed inthe Next Allocation Extent Record. The Length of the Allocation Extent(RBP 24) indicates the length of the allocation extent indicated by theallocation extent record in the form of a byte number. The number ofbytes determined by calculation from the Start Logical Sector Number(RBP 0), Start Offset (RBP 6), End Logical Sector Number (RBP 8) and EndOffset (RBP 14) is equal to the byte number placed in the field of theLength of the Allocation Extent.

[0165] The allocation strategy table designates all allocationstrategies used to arrange data in the logical volume by the AV filesystem. The allocation strategy table is composed of an allocationstrategy table header and an allocation strategy record or records asseen in FIG. 17.

[0166] Referring to FIG. 17, the Allocation Strategy Table Header isrecorded in such a manner as seen in Table 38 below. TABLE 38 AllocationStrategy Table Header BP Length Name Contents  0 8 Signature Signature 8 2 Number of Allocation Strategy Record Uint16 10 6 Reserved #00 bytes

[0167] The Signature (BP 0) has 5 set therein. The Number of AllocationStrategy Record (BP 8) designates the number of allocation strategyrecords in the allocation strategy table. The Reserved (RBP 10) isreserved for future extension and has #00 placed therein.

[0168] An allocation strategy record is used to designate an allocationstrategy. The allocation strategy record is recorded in such a manner asseen in Table 39 below. TABLE 39 Allocation Strategy Record RBP LengthName Contents 0 2 Length of Allocation Strategy Record Uint16 2 2Allocation Strategy Type Uint16 4 1 Allocation Strategy Number Uint8 5 3Reserved #00 bytes 8 x₁ Allocation Strategy Type Dependent Data bytes

[0169] The Length of Allocation Strategy Record (RBP 0) designates thelength of the allocation strategy record in the form of a byte number.The length is a multiple of 8. The Allocation Strategy Type (RBP 2)designates the type of the allocation strategy record. The AllocationStrategy Number (RBP 4) designates what numbered record the allocationstrategy record is in the allocation strategy table, and if theallocation strategy record is the first record, then 0 is placed in theAllocation Strategy Number. The Reserved (RBP 5) is reserved for futureextension and must have #00 placed therein. The Allocation Strategy TypeDependent Data (RBP 8) has placed therein contents which are determinedfor each allocation strategy type.

[0170] In the allocation strategy type 0, the following conditions aremet. First, the allocation extent must be arranged in an area defined bythe Start Logical Sector Number (RBP 8) and the End Logical SectorNumber (RBP 12) of the allocation strategy record. Second, where part ofthe logical sector is allocated to a certain allocation extent, any byteof the logical sector does not belong to another allocation extent.Third, the top of the allocation extent and the top of the logicalsector coincide with each other. The allocation strategy record of theallocation strategy type 0 is recorded in such a manner as seen in Table40 below. TABLE 40 Allocation Strategy Record of Allocation StrategyType 0 RBP Length Name Contents  0 2 Length of Allocation StrategyRecord Uint16(=16)  2 2 Allocation Strategy Type Uint16(=0)  4 1Allocation Strategy Number Uint8  5 3 Reserved #00 bytes  8 4 StartLogical Sector Number Uint3 12 4 End Logical Sector Number Uint32

[0171] The Length of Allocation Strategy Record (RBP 0) has 16 settherein. The Allocation Strategy Type (RBP 2) has 0 set therein. TheAllocation Strategy Number (RBP 4) designates what numbered record theallocation strategy record is in the allocation strategy table, and ifthe allocation strategy record is the first record, then 0 is set in theAllocation Strategy Number. The Reserved (RBP 5) is reserved for futureextension and has #00 set therein. The Start Logical Sector Number (RBP8) designates the number of the top logical sector in which theallocation extent is arranged. The End Logical Sector Number (RBP 12)designates the number of the last logical sector of the area in whichthe allocation extent is arranged.

[0172] The allocation strategy record of the allocation strategy type 1is recorded in such a manner as seen in Table 41 below. TABLE 41Allocation Strategy Record of Allocation Strategy Type 1 RBP Length NameContents  0 2 Length of Allocation Strategy Record Uint16  2 2Allocation Strategy Type Uint16(=1)  4 1 Allocation Strategy NumberUint8  5 3 Reserved #00 bytes  8 2 Number of Zones(=x₁) Uint16 10 6Reserved #00 bytes 16 16x₁ Zone Information Records

[0173] The Length of Allocation Strategy Record (RBP 0) has the lengthof the allocation strategy record, that is, 16+16x₁, (set therein. TheAllocation Strategy type (RBP 2) has 1 set therein. The AllocationStrategy Number (RBP 4) designates what numbered record the allocationstrategy record is in the allocation strategy table, and if theallocation strategy record is the first record, then 0 is set in theAllocation Strategy Number. The Reserved (RBP 5) is reserved for futureextension The Number of Zones (RBP 8) designates the number of zoneinformation records in the allocation strategy record. The Reserved (RBP10) is reserved for future extension and has #00 set therein. The ZoneInformation Records (RBP 16) has placed therein a number of zoneinformation records which are designated by the Number of Zones (RBP 8).The Zone Information Records are recorded in such a manner as seen inTable 42. TABLE 42 Zone Information Record RBP Length Name Contents  0 4Start Logical Sector Number Uint32  4 4 End Logical Sector Number Uint32 8 4 Length of Allocation Unit Uint32 12 4 Reserved #00 bytes

[0174] The Start Logical Sector Number (RBP 0) designates the startlogical sector number of the zone. The End Logical Sector Number (RBP 4)designates the last logical sector number of the zone. The Length ofAllocation Unit (RBP 8) designates an allocation unit to be arrangedinto the zone. The Reserved (RBP 12) is reserved for future extensionand has #00 placed therein.

[0175] The Defect Information Table is used to record logical sectornumbers of defect sectors in the logical volume. The Defect InformationTable is recorded in such a manner as seen in Table 43 below. TABLE 43Defect Information Table BP Length Name Contents  0 8 SignatureSignature  8 4 Number of Defect Sectors(=x₁) Uint32 12 4 Reserved #00bytes 16 4x₁ Defect Sector Addresses bytes

[0176] The data type field of the Signature (BP 0) has 6 set therein.The Number of Detect Sectors (BP 8) designates the number of entries ofthe defect sector address beginning with (BP 16). The Reserved (BP 12)is reserved for future extension and has #00 set therein. The DefectSector Addresses (BP 16) designates logical sector numbers of defectsectors detected in the logical volume. One entry is composed of Uint32,and the values of the logical sector numbers recorded in the DefectSector Addresses are sorted in an ascending order.

[0177] The Extended Attribute Table is composed of an extended attributetable header and an extended attribute record or records as seen in FIG.18. The extended attribute records in the Extended Attribute Table arenumbered consecutively in an ascending order beginning with 0, and suchnumber is called extended attribute record number. A list of theextended attribute records is produced by placing the next record intothe next extended attribute record field and is called extendedattribute record chain. Those extended attribute records which are notused in the extended attribute table make up a list called free extendedattribute record chain.

[0178] The Extended Attribute Table Header is recorded in such a manneras seen in Table 44 below. TABLE 44 Extended Attribute Table Header BPLength Name Contents  0 8 Signature Signature  8 2 Number of ExtendedAttribute Record Uint16 10 2 First Free Extended Attribute Record Uint1612 4 Reserved #00 bytes

[0179] The data type field of the Signature (BP 0) has 7 set herein. TheNumber of Extended Attribute Record (BP 8) designates the number ofextended attribute records in the extended attribute table and is equalto or smaller than #FFF0. The First Free Extended Attribute Record (BP10) designates the first element of the free extended attribute recordchain, and where the extended attribute table does not include a freeextended attribute record therein; #FFFF is set in the First FreeExtended Attribute Record. The Reserved (BP 12) is reserved for futureextension and has #00 set therein.

[0180] The Extended Attribute Record is recorded in such a manner asseen in Table 45 below. TABLE 45 Extended Attribute Record RBP LengthName Content 0  2 Next Extended Attribute Record Uint16 2 30 ExtendedAttribute Information bytes

[0181] The Next Extended Attribute Record (RBP 0) designates the numberof the next extended attribute record which composes the extendedattribute record chain. Where the extended attribute record is the lastextended attribute record, #FFFF is set in the Next Extended AttributeRecord.

[0182] Most of existing file systems are designed under the presumptionthat defect sector processing of a medium is performed in a layerpositioned below the file system (for example, replacement processing ina drive). In those file systems, it cannot be discriminated where adefective sector is, and although data can be accessed at a raw transferrate of the drive where the file system tries to access a defect-freeportion of a medium, where the file system tries to access a portion ofthe medium for which replacement processing has been performed, data canbe accessed only at a transfer rate much lower than the raw transferrate of the drive.

[0183] Such a construction as described above has no problem withconventional computer applications because, although it is demanded toimprove the average access time, estimation of individual access timesis not demanded. However, in audio and video applications, if data arenot supplied by a fixed amount in a fixed time, then sound or an imagecannot be recorded or reproduced correctly, and therefore, it isrequired that a file system can perform estimation of a time requiredfor data accessing.

[0184] Therefore, the present file system introduces the presumptionthat defective sector processing need not be performed in a lower layerand makes it possible to accurately estimate a time required for thefile system to access data. Further, in the present file system, a fieldor a flag for defective sector processing which has not been used inconventional file systems is prepared, and therefore, processing of adefective sector can be performed using the field or flag. Here, anexample of performing defective sector processing using the functionprepared by the present file system is described.

[0185] Generally, a defective sector is detected in one of the followingcases. First, an error occurs during writing, and a defective sector isdetected. Second, although writing is completed regularly, an error isdetected when the written portion is read out immediately after thewriting. Third, although writing and reading out immediately after thewriting are completed regularly, an error is detected when reading outis performed after lapse of a time.

[0186] In the first or second case, an error can be detected and dealtwith upon writing by performing reading out immediately after writingand performing an operation of confirming that the data have beenwritten correctly. The operation is called Write and Verify.

[0187] In the third case, an error is caused by a fault provided by duston or damage to the optical disc. For this case, no completecountermeasure is available. However, the possibility of data loss canbe reduced significantly by employing multiple writing. The present filesystem principally employs the two techniques of the Write and Verifyand the multiple writing to perform processing of a defective sector.

[0188] The volume structure is defined by the Volume StructureDescriptor, Media Information Descriptor, Drive Information Descriptorand Extended Data Descriptor. A defective-sector for such information isdealt with in the following manner.

[0189] The volume structure descriptor, media information descriptor,drive information descriptor and extended data descriptor are managed byeach MIA. The MIA can record a non-defective sector with certainty byperforming write and verify without fail upon recording. Further, takinga defect, which may occur after recording, into consideration, two MIAsare recorded in an overlapping relationship at different locations, andalso two MIA maps for managing a situation of use in the MIAs arerecorded in an overlapping relationship at different locations.

[0190] Further, in a logical volume which is defined by the volumemanagement system, defect management by slipping or linear replacementcan be performed for each of partitions which compose the logicalvolume.

[0191] A defective sector is dealt with in the following manner by theAV file system. In particular, when the AV file system performs writinginto the AV file system descriptor, it performs Write and Verify toconfirm that writing has been performed correctly. If the AV file systemhas failed in the writing, then it writes the AV file system descriptorat a different location and re-writes contents of the Logical VolumeContents Use field. Further, the AV file system writes two AV filesystem descriptors at two different locations to assure a high degree ofreliability.

[0192] When the AV file system performs writing into sectors in theMIAs, it performs Write and Verify to confirm that writing has beenperformed correctly. If the AV file system has failed in the writing,then it writes #FFF0 into the entry field of one of the MIA maps, andthen performs a same sequence of operations for a sector in the otherMIA. Further, the AV file system writes the MIAs at two locations of thelogical volume to assure a high degree of reliability.

[0193] Each defective sector detected during operation by the AV filesystem is registered into the defect information table so that it maythereafter not be used any more.

[0194] It sometimes occurs that, for data recorded in an allocationextent, a Write and Verify operation cannot be performed from a demandfor the transfer rate, and only Write operation is performed. In anycase, when a defective sector is detected, the AV file system determinesthe portion as an independent allocation extent and places 10 into theallocation extent record status of the allocation extent record of thesame so that the allocation extent may be placed into the defectiveallocation extent record chain. If a defective sector is detected in anallocation extent upon reading out, then the AV file system places 11into the allocation extent record chain. When releasing of theallocation extent is performed, the defective sector is checked, and thedefective sector portion is registered as an allocation extent, whoseallocation extent record status is 10, into the defective allocationextent record chain.

[0195]FIG. 19 shows a constriction of a recording and/or reproductionapparatus to which the present invention is applied. The recordingand/or reproduction apparatus is generally denoted at 1 and constructedsuch that, when an optical disc 8 is loaded into it, it either records avideo signal and an audio signal as well as PC (Personal Computer) datasupplied thereto from the outside onto the optical disc 8 or reads out asignal recorded on the optical disc 8 and outputs the signal to theoutside.

[0196] A user inputting/outputting section 2 includes a key panel 11 anda liquid crystal display unit (LCD) 12. The key panel 11 generates asignal corresponding to an operation thereof by a user and supplies thesignal to a system control unit 5. The LCD 12 displays a state of therecording and/or reproduction apparatus 1, information regarding theoptical disc 8 loaded in the recording and/or reproduction apparatus 1and so forth in response to the signal supplied thereto from the systemcontrol unit 5.

[0197] An AV inputting/outputting section 3 includes a pair ofencoder/decoders 13 and 14 and a multiplexer/demultiplexer 15 which arecontrolled in response to a signal supplied thereto from the systemcontrol unit 5. Further, the AV inputting/outputting section 3 suppliesa signal representative of each of the encoder/decoders 13 and 14 andthe multiplexer/demultiplexer 15 to the system control unit 5.

[0198] The encoder/decoder 13 compresses (encodes), upon recording, avideo signal supplied thereto from the outside and outputs video data ofa predetermined system corresponding to the video signal to themultiplexer/demultiplexer 15. But upon reproduction, the encoder/decoder13 decompresses (decodes) video data of the predetermined systemsupplied thereto from the multiplexer/demultiplexer 15 and outputs thedecompressed (decoded) video data. The encoder/decoder 14 compresses(encodes), upon recording, an audio signal supplied thereto from theoutside and outputs audio data of a predetermined system correspondingto the audio signal to the multiplexer/demultiplexer 15. But uponreproduction, the encoder/decoder 14 decompresses (decodes) audio dataof the predetermined system supplied thereto from themultiplexer/demultiplexer 15 and outputs the decompressed (decoded)audio data to the outside.

[0199] The multiplexer/demultiplexer 15 multiplexes, upon recording,video data and audio data of the predetermined systems supplied theretofrom the encoder/decoders 13 and 14, respectively, and outputs themultiplexed data to a drive unit 7. On the other hand, uponreproduction, the multiplexer/demultiplexer 15 demultiplexes multiplexedvideo data and audio data supplied thereto from the drive unit 7 andoutputs the video data to the encoder/decoder 13 and outputs the audiodata to the encoder/decoder 14.

[0200] A PC data inputting/outputting unit 4 includes an interface 16and controls the interface 16 in response to a signal supplied theretofrom the system control unit 5 so that a signal representative of astate of the interface 16 is outputted to the system control unit 5. Theinterface 16 receives PC data of a predetermined form supplied theretofrom an external personal computer (not shown) or the like as an inputthereto, converts the PC data into data which can be read by the driveunit 7, and outputs the data to the drive unit 7. Further, the interface16 outputs data supplied thereto from the drive unit 7 in apredetermined form to the external personal computer or the like.

[0201] The system control unit 5 controls the user inputting/outputtingsection 2, AV inputting/outputting section 3, PC datainputting/outputting unit 4 and file management unit 6 based on statesof the user inputting/outputting unit 2, AV inputting/outputting section3, PC data inputting/outputting unit 4 and file management unit 6.

[0202] The file management unit 6 controls the drive unit 7 in responseto a signal from the system control unit 5 and supplies a signalcorresponding to a state of the drive unit 7 to the system control unit5.

[0203] The drive unit 7 operates a buffer 17, an ECC circuit 18, amodulation/demodulation circuit 19 and a pickup 20 and operates them inresponse to signals from the file management unit 6 to record a signalonto the optical disc 8 or read out a signal from the optical disc 8.

[0204] The buffer 17 temporarily stores data supplied thereto from theAV inputting/outputting section 3 or the PC data inputting/outputtingunit 4 and outputs the data to the ECC (Error Correction Code) circuit18 in such a manner that they may not be interrupted. Further, thebuffer 17 temporarily stores data supplied thereto from the ECC circuit18 and supplies the data to the AV inputting/outputting section 3 or thePC data inputting/outputting unit 4 in such a manner that they may notbe interrupted.

[0205] The ECC circuit 18 adds error correction codes to data suppliedthereto from the buffer 17 and outputs resulting data to themodulation/demodulation circuit 19. Further, the ECC circuit 18 performserror correction of data supplied thereto from themodulation/demodulation circuit 19 based on error correction codes andoutputs resulting data to the buffer 17.

[0206] The modulation/demodulation circuit 19 modulates data suppliedthereto from the ECC circuit 18 into data of a predetermined system andoutputs the resulting data to the pickup 20. Further, themodulation/demodulation circuit 19 demodulates data supplied theretofrom the pickup 20 in accordance with the predetermined system andoutputs the demodulated data to the ECC circuit 18.

[0207] The pickup 20 records data onto the optical disc 8 loaded in therecording and/or reproduction apparatus 1 based on data supplied theretofrom the modulation/demodulation circuit 19. Further, the pickup 20reads data recorded on the optical disc 8 and outputs the read data tothe modulation/demodulation circuit 19.

[0208]FIGS. 20A and 20B illustrate a relationship between the amount ofdata recorded in the buffer 17 and the rate at which data are writteninto the buffer 17 during reproduction. The readout rate Rout of dataoutputted from the buffer 17 is controlled to a fixed value higher thana predetermined value in such a manner that outputting of signals fromthe encoder/decoders 13 and 14 may not be interrupted. The data writerate of data supplied to the buffer 17 exhibits a fixed value Rin asseen from FIG. 20B when sectors of the optical disc 8 on which apredetermined file is recorded are read. In the meantime, the data writerate exhibits zero while the pickup 20 moves between tracks of theoptical disc 8 or when the pickup 20 waits rotation of the optical disc8 until a predetermined sector comes to a position at which it can beread by the pickup 20 (for a time Ts of FIG. 20B).

[0209] Consequently, when the data write rate to the buffer 17 is 0,since the data recorded in the buffer 17 are only read out at thereadout rate Rout, the amount of the data decreases suddenly as seenfrom FIG. 20A. The amount of data which can be stored into the buffer 17is determined based on the fixed value Rin and the data readout rate insuch a manner that reading out of data may not be interrupted.

[0210]FIG. 21 illustrates a construction of a file recorded on theoptical disc 8. Blocks are obtained by dividing the entire disc with anequal size, and the blocks are physically continuous to each other.Further, in each of the blocks, transfer of data is executed at the rateRin. Data of a file are recorded over one or a plurality of blocks.Accordingly, the blocks are divided into those blocks in which part of afile or an entire file is recorded and those blocks in which data of anyfile are not recorded. Where the amount of data of a file recorded in ablock is smaller than the magnitude of the block, the block immediatelyprior to the file is recorded fully with data.

[0211]FIGS. 22A to 22D illustrate the construction of a file and theamount of data stored in the buffer 17. FIG. 22A illustrates filesrecorded in blocks. A block 31 is recorded fully with data of the file.Another block 32 next to the block 31 is recorded partially with data ofthe file. A further block 33 is recorded fully with data of anotherfile. A still further block 34 next to the 33 is recorded partially withdata of the file.

[0212]FIG. 22B illustrates the write rate into the buffer 17 when theblocks illustrated in FIG. 22A are read out. When the block 31 is readout, since it is physically continuous, the write rate into the buffer17 is the fixed rate of Rin. Similarly, when the block 32 is read out,when the block 33 is read out, and when the block 34 is read out, thewrite rate into the buffer 17 is the fixed rate of Rin.

[0213] When reading out of the block 32 is performed after reading outof the block 31 is ended, the block 31 and the block 32 are notnecessarily be physically continuous to each other, and if they are notcontinuous to each other, then the pickup 20 waits rotation of theoptical disc 8 while it moves between tracks of the optical disc 8 oruntil a predetermined sector comes to the position at which it can beread by the pickup 20. Therefore, a period Ts1 within which the writerate into the buffer 17 is reduced to 0 is present. Similarly, whenreading out of the block 33 is performed after reading out of the block32, another period Ts2 within which the write rate into the buffer 17 isreduced to zero is present, and when reading out of the block 34 isperformed after reading out of the block 33 is completed, a period Ts3within which the write rate into the buffer 17 is reduced to zero ispresent.

[0214]FIG. 22C illustrates the data readout rate from the buffer 17. Thedata readout rate normally exhibits the fixed value Rout. FIG. 22Dillustrates the amount of data stored in the buffer 17. Similarly as inFIG. 20A, the data amount of the buffer 17 increases at a ratecorresponding to the difference between the write rate Rin and thereadout rate Rout, and when the data write rate into the buffer 17exhibits zero, since only reading out from the buffer 17 proceeds, theamount of data recorded in the buffer 17 decreases suddenly.Particularly when the data write rate becomes zero after the block 32 orthe block 34 which is recorded only partially with data of a file isread out, the amount of data recorded in the buffer 17 decreases at ahigh rate, and consequently, in order to prevent possible underflow, thebuffer 17 must have a storage capacity higher than a predeterminedlevel.

[0215]FIG. 23 illustrates another example of a construction of a filerecorded on the optical disc 8. In the construction illustrated in FIG.23, a block recorded partially or entirely with data of a file isrecorded with the data of the file over more than one half the blockwithout fail.

[0216]FIGS. 24A to 24D illustrate a variation of the amount of data ofthe buffer 17 where the file is constructed in such a manner asillustrated in FIG. 23. FIG. 24A illustrates files recorded in blocks.In FIG. 24A, a file is recorded over more than one half of each ofblocks 51 to 54.

[0217]FIG. 24B illustrates the write rate into the buffer 17 when theblocks illustrated in FIG. 24A are read out. When the block 51 is to beread out, the write rate into the buffer 17 is the fixed rate of Rinsince the block 51 is physically continuous. Similarly, when the block52 is read out, when the block 53 is read out and when the block 54 isread out, the write rate into the buffer 17 is the fixed rate of Rin.

[0218] When reading out of the block 52 is performed after reading outof the block 51 is ended, if they are physically spaced away from eachother, then a period Ts4 within which the write rate into the buffer 17is reduced to zero is present. Similarly, when reading out of the block53 is performed after reading out of the block 52 is ended, a period Ts5within which the write rate into the buffer 17 is reduced to zero ispresent, and when reading out of the block 54 is performed after readingout of the block 53 is ended, a period Ts6 within which the write rateinto the buffer 17 is reduced to zero is present.

[0219]FIG. 24C illustrates the data readout rate from the buffer 17. Thedata read out rate always has the fixed value Rout. FIG. 24D illustratesa variation of the amount of data stored in the buffer 17. When the datawrite rate into the buffer 17 is reduced to zero, the amount of datastored in the buffer 17 decreases suddenly. When compared with thestored data amount of the buffer illustrated in FIG. 22D, since each ofthe blocks 51, 52, 53 and 54 has data recorded over more than the fixedamount (½) thereof, the possibility that the amount of data stored inthe buffer 17 may approach zero is lower than that illustrated in FIG.22D.

[0220]FIGS. 25A and 25B illustrate recording processing of a file intoblocks by the file management unit 6. Processing in a case wherein dataof a file are recorded in blocks 71 to 73 and a file 75 of a data amountsmaller than one half a block 74 is recorded into the block 74 newly asseen in FIG. 25A is described. As seen from FIG. 25B, the file stored inthe block 73 is divided leaving a front half portion 81 which occupiesone half the block 73, and the other rear half 82 is moved to the top ofthe block 74. The file 75 is recorded following the rear half portion 82of the block 74.

[0221] As described above, any block in which part or the entirety of afile is recorded with the file over one half the block.

[0222] The processing described above can be summarized in such a manneras illustrated in a flow chart of FIG. 26. Referring to FIG. 26, thefile management unit 6 discriminates in step S31 whether or not theamount of data to be recorded into a particular block is smaller thanone half a block. If the amount of data to be recorded is smaller thanone half a block, then the control advances to step S32, in which thedata of the rear half of a block immediately prior to the particularblock are divided and recorded into the particular block. Then in stepS33, the file management unit 6 records the data of the amount smallerthan one half a block continuously into the particular block.

[0223] Then, in step S34, the file management unit 6 discriminateswhether or not all data have been recorded. Then, if it is discriminatedthat all data have not been recorded, then the control returns to stepS31 to repeat the processing described above.

[0224] If it is discriminated in step S31 that the amount of data to berecorded is not smaller than one half a block, then the control advancesto step S35, in which the file management unit 6 discriminates whetheror not the amount of data to be recorded is smaller than one block. Ifit is discriminated that the amount of data to be recorded is notsmaller than one block, then the control advances to step S36, in whichthe file management unit 6 records the data for one block, whereafterthe control advances to step S34.

[0225] If it is discriminated in step S35 that the amount of data to berecorded is smaller than one block, then the control advances to stepS37, in which the file management unit 6 records the data into oneblock, whereafter the control advances to step S34.

[0226] If it is discriminated in step S34 that all data have beenrecorded, then the processing is ended.

[0227]FIGS. 27A and 27B illustrate processing of dividing a recordedinto blocks. Processing when one file is recorded in blocks 91 to 93 andthis file is divided into a file from the start point of the block 91 toa dividing point of the block 92 (which is positioned forwardly one halfthe block 92) and another file from the dividing point of the block 92to the end point of the block 93 as seen in FIG. 27A is described. Asseen from FIG. 27B, the data of the block 91 preceding to a portion 95of the block 92 from the start point to the dividing point are dividedinto two portions, and the rear half portion 94 of them is moved to theblock 92. A front portion 95 of the block 92 is stored following therear half portion 94 moved to the block 92. On the other hand, theportion 96 of the block 92 from the dividing point to the end point isstored into a new block 101.

[0228]FIGS. 28A and 28B illustrate another example of dividingprocessing of a file. Processing when a single file recorded in blocks111 to 114 is divided at a dividing point positioned forwardly of onehalf position of the block 112 is described.

[0229] If the block 111 has an area sufficient to allow recording of aportion 115 of the block 112 from its start point to the dividing pointas seen in FIG. 28B, then the block 115 is recorded following the filerecorded already in the block 111. A portion 116 of the block 112 fromthe dividing point to the end of the data is moved to a positionbeginning with the start point of the block 112. Data of the block 113recorded in the overall range thereof are divided into two portions, andthe front half portion 117 of them is moved to the block 112 andrecorded following the portion 116 of the block 112. The other rear halfportion 118 of the block 113 is moved to a position beginning with thestart point of the block 113.

[0230]FIGS. 29A and 29B illustrate a further example of processing ofdividing a file recorded in blocks. Processing when a single filerecorded in blocks 121 to 123 is divided at a dividing point given as amiddle point of the block 122 as seen in FIG. 29A is described. As seenfrom FIG. 29B, a portion 124 of the block 122 from the dividing point tothe end of the data is stored at the top of a new block 131. The file ofthe block 123 recorded in the overall range thereof is divided into twoportions, and the front half portion 125 of them is stored into theblock 131 following the portion 124, and the other rear half portion 126is moved to the top of the block 123.

[0231] As described above, even if a file is divided, any block isrecorded with the file over more than one half thereof.

[0232] The processing of dividing a file illustrated in FIGS. 27A and27B wherein the magnitude of data from a start point to a dividing pointof a block is smaller than the magnitude of a block and the magnitude ofthe data rearwardly of the dividing point is equal to or more than onehalf the magnitude of a block is such as illustrated in a flow chart ofFIG. 30. Referring to FIG. 30, first in step S41, the file managementunit 6 moves data of that portion of a block having a dividing pointwhich is positioned rearwardly of the dividing point to a new block. Instep S42, the file management unit 6 moves predetermined data of anotherblock immediately preceding to the block having the dividing point to aposition beginning with the start point of the block having the dividingpoint, and moves the data of the block having the dividing point whichranges from the start point to the dividing point to the positionfollowing the thus moved predetermined data.

[0233] The processing of dividing a file illustrated in FIGS. 28A and28B wherein the magnitude of a free portion immediately forwardly of ablock having a dividing point is larger than the magnitude of data fromthe start point to the dividing point of the block having the dividingpoint and the magnitude of data rearwardly of the dividing point issmaller than-one half the magnitude of a block is such as illustrated inFIG. 31. Referring to FIG. 31, first in step S51, the file managementunit 6 moves the data from the start point to the dividing point of theblock having the dividing point to the free portion of the blockimmediately preceding to the block having the dividing point. In stepS52, the file management unit 6 moves predetermined data immediatelyfollowing the block having the dividing point to the position rearwardlyof the data of the block having the dividing point.

[0234] The processing of dividing a file illustrated in FIGS. 29A and29B wherein the magnitude of data from the start point to a dividingpoint of a block is equal to or later than one half the magnitude of ablock and the magnitude of data rearwardly of the dividing point issmaller than one half the magnitude of a block is such as illustrated inthe flow chart of FIG. 32. Referring to FIG. 32, the file managementunit 6 moves the data rearwardly of the dividing point to a new block instep S61. In step S62, the file management unit 6 moves predetermineddata of another block immediately following the block having thedividing point to the position rearwardly of the data of the new block.

[0235] While the processing described above is performed depending uponwhether or not the magnitude of data from the start point to thedividing point of a block is equal to or larger than one half themagnitude of a block, it may be performed otherwise depending uponwhether or not magnitude of such data is equal to or larger than(n−1)/n(n=2, 3, 4, 5, . . . ).

[0236]FIGS. 33A and 33B illustrate processing of compressing free areasof blocks where the sum of free areas of three successive blocks isequal to or larger the area of one block. As seen from FIG. 33A, the sumof free areas of blocks 141 to 143 is equal to or larger than the areaof one block. Data stored in the block 142 are divided into a portion144 having a magnitude equal to the magnitude of the free area of theblock 141 and the remaining portion 145.

[0237] As seen in FIG. 33B, the portion 144 of the block 142 is moved tothe free area of the block 141. The portion 145 of the block 142 ismoved to the top of the block 142, and data 146 of the block 143 aremoved to the block 142 and stored following the portion 145. The block143 becomes free.

[0238] In this manner, the free area of the blocks 141 and 142 can beminimized and the block 143 can be made free.

[0239] The processing described above can be summarized as illustratedin a flow chart of FIG. 34. Referring to FIG. 34, the file managementunit 6 discriminates in step S71 whether or not the sum of free areas ofthree blocks is equal to or larger than the area of one block. If it isdiscriminated that the sum of free areas of the three blocks is equal toor larger than the area of one block, then the control advances to stepS72, in which data of an amount equal to the free area of the top blockare moved from the intermediate block to the free area of the top block.Then in step S73, the file management unit 6 moves data of the lastblock into the resulting free area of the intermediate block, therebyending the processing.

[0240] If it is discriminated in step S71 that the sum of the free areasof the three blocks is not equal to or larger than the area of oneblock, then the processing is ended.

[0241] As described above, any block in which part or the entire of afile is recorded is recorded with data over one half or more of theblock, and periods in which the write rate is reduced to zero aredispersed. Consequently, even if the capacity of the buffer 17 is small,the output is not interrupted.

[0242] It is to be noted that the providing medium to be used to provideto a user a computer program for achieving such processing as describedhereinabove may be a recording medium such as a magnetic disc, a CD-ROMor a solid state memory or a communication medium such as a network or asatellite.

What is claimed is:
 1. A recording and/or reproduction apparatus forrecording and/or reproducing AV data onto and/or from a disc typerecording medium, comprising: first recording means for recording a fileof AV data; and second recording means for recording managementinformation for the file to at least two locations of a logical volume.2. A recording and/or reproduction apparatus according to claim 1,wherein the management information recorded by said second recordingmeans includes information at least of a defective sector or sectors andan unused sector or sectors.
 3. A file management method for a recordingand/or reproduction apparatus for recording and/or reproducing AV dataonto and/or from a disc type recording medium, comprising: a firstrecording step of recording a file of AV data; and a second recordingstep of recording management information for the file to at least twolocations of a logical volume.
 4. A providing medium for providing aprogram which can be read by a computer for causing a recording and/orreproduction apparatus for recording and/or reproducing AV data ontoand/or from a disc type recording medium to execute: a first recordingstep of recording a file of AV data; and a second recording step ofrecording management information for the file to at least two locationsof a logical volume.
 5. A recording and/or reproduction apparatus,comprising: unit recording means for recording units of informationwhich can be recorded onto a disc type recording medium; setting meansfor setting lengths of the units of information to be recorded by saidunit recording means; and identification information recording means forrecording, in response to a file recorded on the disc type recordingmedium, identification information for identification of the length ofthe unit adopted when the file is recorded from among the units of thelength set by said setting means.
 6. A recording and/or reproductionapparatus according to claim 5, wherein said setting means sets thelength of the unit of AV data longer than the length of the unit ofcomputer data.
 7. A recording and/or reproduction apparatus according toclaim 5, further comprising control means for dividing the disc typerecording medium into a plurality of blocks and controlling so that datamay be recorded into an area of any of the divided blocks which is equalto or larger than one half the block.
 8. A recording and/or reproductionapparatus according to claim 5, further comprising control means fordividing each of tracks of the disc type recording medium, onto whichinformation is to be recorded, into n blocks and controlling so thatdata may be recorded into an area of any of the divided blocks which isequal to or larger than (n-1)/n of the block, n being an integer equalto or larger than
 2. 9. A file management method for a recording and/orreproduction apparatus for recording and/or reproducing information ontoand/or from a disc type recording medium, comprising: a unit recordingstep of recording units of information which can be recorded onto thedisc type recording medium; a setting step of setting lengths of unitsof information to be recorded in the unit recording step; and anidentification information recording step of recording, in response to afile recorded on the disc type recording medium, identificationinformation for identification of the length of the unit adopted whenthe file is recorded from among the units of the length set by saidsetting means.
 10. A providing medium for providing a program which canbe read by a computer for causing a recording and/or reproductionapparatus for recording and/or reproducing AV data onto and/or from adisc type recording medium to execute: a unit recording step ofrecording units of information which can be recorded onto the disc typerecording medium; a setting step of setting lengths of units ofinformation to be recorded in the unit recording step; and anidentification information recording step of recording, in response to afile recorded on the disc type recording medium, identificationinformation for identification of the length of the unit adopted whenthe file is recorded from among the units of the length set by saidsetting means.